{ "title": "Published drinking water hardness by U.S. city", "publisher": "My Home Water System", "operator": "Aidren LLC", "method": "Each figure is copied as published by the city's water utility, with its period and source. USGS classes: 0-60 mg/L soft, 61-120 moderately hard, 121-180 hard, over 180 very hard.", "usgs_source": "https://www.usgs.gov/water-science-school/science/hardness-water", "updated": "2026-10-27", "cities": [ { "city": "Chandler", "state": "AZ", "slug": "chandler", "hardness_facts": [ { "utility": "City of Chandler", "measure": "Total hardness", "value_as_published": "173-288 mg/L (10.1-16.8 grains per gallon)", "period": "Calendar year 2025", "source_title": "Chandler 2025 Drinking Water Quality Consumer Confidence Report", "source_url": "https://www.chandleraz.gov/sites/default/files/departments/water/City-of-Chandler-2025-Drinking-Water-Quality-Consumer-Confidence-Report.pdf" } ], "published_span_mg_per_l": [ 173, 288 ], "span_converted_from_grains": false, "usgs_class": "hard to very hard", "usgs_class_source": "https://www.usgs.gov/water-science-school/science/hardness-water", "notes": [ "Chandler disinfects with chlorine. Its 2025 residual averaged 0.93 ppm.", "Chandler's undated water quality FAQ gives a different figure: an average of 16.5 grains per gallon within a range of 5 to 20." ], "local_details": { "disinfectant": { "text": "Chandler disinfects its water with chlorine before it enters the city pipes.", "kind": "chlorine", "source_title": "Chandler 2025 Drinking Water Quality Consumer Confidence Report", "source_url": "https://www.chandleraz.gov/sites/default/files/departments/water/City-of-Chandler-2025-Drinking-Water-Quality-Consumer-Confidence-Report.pdf", "evidence_ids": [ "CHANDL-L-01" ] }, "source_water": { "text": "Chandler treats Salt, Verde and Colorado River water at its Pecos and Santan Vista plants and pumped groundwater from 27 wells in 2025.", "source_title": "Chandler 2025 Drinking Water Quality Consumer Confidence Report", "source_url": "https://www.chandleraz.gov/sites/default/files/departments/water/City-of-Chandler-2025-Drinking-Water-Quality-Consumer-Confidence-Report.pdf", "evidence_ids": [ "CHANDL-L-02" ] }, "seasonal": { "text": "Chandler says the flavor of its water can change at certain times of the year, depending on the source.", "source_title": "Chandler 2025 Drinking Water Quality Consumer Confidence Report", "source_url": "https://www.chandleraz.gov/sites/default/files/departments/water/City-of-Chandler-2025-Drinking-Water-Quality-Consumer-Confidence-Report.pdf", "evidence_ids": [ "CHANDL-L-03" ] } }, "sources_checked_on": "2026-10-26", "site": "https://chandlerwatersystems.com/", "brand": "Chandler Water Systems by My Home Water System", "taking_requests": true }, { "city": "Gilbert", "state": "AZ", "slug": "gilbert", "hardness_facts": [ { "utility": "Town of Gilbert", "measure": "Total hardness", "value_as_published": "Average 10.79 grains per gallon (184.44 mg/L), range 6.61-17.54 grains per gallon", "period": "Calendar year 2025", "source_title": "Gilbert 2025 Annual Drinking Water Quality Report", "source_url": "https://www.gilbertaz.gov/home/showpublisheddocument/54483/639183476630708025" } ], "published_span_mg_per_l": [ 113, 300 ], "span_converted_from_grains": true, "usgs_class": "moderately hard to very hard", "usgs_class_source": "https://www.usgs.gov/water-science-school/science/hardness-water", "notes": [ "Gilbert disinfects with chlorine. Its 2025 residual averaged 0.92 ppm." ], "local_details": { "disinfectant": { "text": "Gilbert disinfects plant water with ozone and chlorine, and its pipes carry chlorine.", "kind": "chlorine", "source_title": "Gilbert water quality page", "source_url": "https://www.gilbertaz.gov/departments/public-works/water/water-quality-91", "evidence_ids": [ "GILBER-L-01" ] }, "source_water": { "text": "Gilbert gets Salt and Verde River water through Salt River Project canals and Colorado River water through the Central Arizona Project, plus groundwater from 17 wells.", "source_title": "Gilbert water quality page", "source_url": "https://www.gilbertaz.gov/departments/public-works/water/water-quality-91", "evidence_ids": [ "GILBER-L-02" ] }, "seasonal": { "text": "Gilbert leans on groundwater during high demand and when canals are dried out for maintenance.", "source_title": "Gilbert water quality page", "source_url": "https://www.gilbertaz.gov/departments/public-works/water/water-quality-91", "evidence_ids": [ "GILBER-L-03" ] } }, "sources_checked_on": "2026-10-26", "site": "https://gilbertwatersystems.com/", "brand": "Gilbert Water Systems by My Home Water System", "taking_requests": true }, { "city": "Mesa", "state": "AZ", "slug": "mesa", "hardness_facts": [ { "utility": "City of Mesa", "measure": "Average hardness, City Zone", "value_as_published": "About 12 grains per gallon", "period": "Calendar year 2025", "source_title": "Mesa 2025 Water Quality Consumer Confidence Report", "source_url": "https://www.mesaaz.gov/files/content/public/v/16/utilities/water-wastewater/water-quality/english-water-quality-report-2025.pdf" }, { "utility": "City of Mesa", "measure": "Average hardness, Eastern and Southern Zones", "value_as_published": "16 grains per gallon", "period": "Calendar year 2025", "source_title": "Mesa 2025 Water Quality Consumer Confidence Report", "source_url": "https://www.mesaaz.gov/files/content/public/v/16/utilities/water-wastewater/water-quality/english-water-quality-report-2025.pdf" } ], "published_span_mg_per_l": [ 205, 274 ], "span_converted_from_grains": true, "usgs_class": "very hard", "usgs_class_source": "https://www.usgs.gov/water-science-school/science/hardness-water", "notes": [ "The City Zone gets Salt River Project water from the Salt and Verde Rivers. The Eastern and Southern Zones get Central Arizona Project water from the Colorado River. Groundwater wells supply all zones.", "Mesa's undated water quality concerns page gives a wider range of 12 to 22 grains per gallon depending on the source serving the area." ], "local_details": { "disinfectant": { "text": "Mesa disinfects with chlorine dioxide and chlorine before water enters its pipes.", "kind": "chlorine", "source_title": "Mesa 2025 Water Quality Consumer Confidence Report", "source_url": "https://www.mesaaz.gov/files/content/public/v/16/utilities/water-wastewater/water-quality/english-water-quality-report-2025.pdf", "evidence_ids": [ "MESA-L-01" ] }, "seasonal": { "text": "Mesa says every zone may get groundwater or a blend of surface water and groundwater at different times of the year, and some customers get only well water at times.", "source_title": "Mesa 2025 Water Quality Consumer Confidence Report", "source_url": "https://www.mesaaz.gov/files/content/public/v/16/utilities/water-wastewater/water-quality/english-water-quality-report-2025.pdf", "evidence_ids": [ "MESA-L-02" ] } }, "sources_checked_on": "2026-10-26", "site": "https://mesawatersystems.com/", "brand": "Mesa Water Systems by My Home Water System", "taking_requests": true }, { "city": "Phoenix", "state": "AZ", "slug": "phoenix", "hardness_facts": [ { "utility": "City of Phoenix", "measure": "Total hardness", "value_as_published": "172-302 ppm (10-17.6 grains per gallon), range only", "period": "Calendar year 2025", "source_title": "City of Phoenix 2025 Water Quality Report", "source_url": "https://phoenix.gov/waterqualityreport" } ], "published_span_mg_per_l": [ 172, 302 ], "span_converted_from_grains": false, "usgs_class": "hard to very hard", "usgs_class_source": "https://www.usgs.gov/water-science-school/science/hardness-water", "notes": [ "Water from the Salt and Verde Rivers is delivered through the Salt River Project canal network. About 20 city wells supplied about two percent of the water." ], "local_details": { "disinfectant": { "text": "Phoenix disinfects its entire supply, well water and treated surface water, with chlorine.", "kind": "chlorine", "source_title": "Phoenix 2025 Water Quality Report", "source_url": "https://www.phoenix.gov/content/dam/phoenix/waterservicessite/documents/wsdprimarywqr.pdf", "evidence_ids": [ "PHOENI-L-01" ] }, "source_water": { "text": "Phoenix gets almost all of its water from the Salt, Verde and Colorado rivers through Salt River Project canals and the Central Arizona Project, and the rest from about 20 city wells.", "source_title": "Phoenix 2025 Water Quality Report", "source_url": "https://www.phoenix.gov/content/dam/phoenix/waterservicessite/documents/wsdprimarywqr.pdf", "evidence_ids": [ "PHOENI-L-02" ] }, "seasonal": { "text": "Phoenix says taste and odor changes are often seasonal and strongest near fall, when algae grow in the canals.", "source_title": "Phoenix seasonal taste and odor FAQ", "source_url": "https://www.phoenix.gov/content/dam/phoenix/waterservicessite/documents/seasonal_taste_odor_faqs.pdf", "evidence_ids": [ "PHOENI-L-03" ] } }, "sources_checked_on": "2026-10-26", "site": "https://phoenixhomewatersystems.com/", "brand": "Phoenix Home Water Systems by My Home Water System", "taking_requests": true }, { "city": "Scottsdale", "state": "AZ", "slug": "scottsdale", "hardness_facts": [ { "utility": "City of Scottsdale", "measure": "Approximate hardness, south of Indian School Rd", "value_as_published": "13-15 grains per gallon (230-260 mg/L)", "period": "Calendar year 2025", "source_title": "Scottsdale 2026 Water Quality Report", "source_url": "https://www.scottsdaleaz.gov/docs/default-source/scottsdaleaz/water/water-quality/annual-reports/2026-water-quality-report.pdf?sfvrsn=18a67596_1" }, { "utility": "City of Scottsdale", "measure": "Approximate hardness, Indian School Rd to Chaparral Rd", "value_as_published": "13-17 grains per gallon (215-285 mg/L)", "period": "Calendar year 2025", "source_title": "Scottsdale 2026 Water Quality Report", "source_url": "https://www.scottsdaleaz.gov/docs/default-source/scottsdaleaz/water/water-quality/annual-reports/2026-water-quality-report.pdf?sfvrsn=18a67596_1" }, { "utility": "City of Scottsdale", "measure": "Approximate hardness, north of Chaparral Rd", "value_as_published": "13-17 grains per gallon (230-290 mg/L)", "period": "Calendar year 2025", "source_title": "Scottsdale 2026 Water Quality Report", "source_url": "https://www.scottsdaleaz.gov/docs/default-source/scottsdaleaz/water/water-quality/annual-reports/2026-water-quality-report.pdf?sfvrsn=18a67596_1" } ], "published_span_mg_per_l": [ 215, 290 ], "span_converted_from_grains": false, "usgs_class": "very hard", "usgs_class_source": "https://www.usgs.gov/water-science-school/science/hardness-water", "notes": [ "Scottsdale's 2025 supply was 71 percent Central Arizona Project, 13 percent Salt River Project, 8 percent groundwater and 8 percent recycled water.", "Scottsdale disinfects with chlorine. Its 2025 residual averaged 0.64 ppm.", "The city's undated hard water fact sheet lists higher figures for the same areas, up to 22-25 grains per gallon south of Indian School Rd. The current annual report figures are shown above." ], "local_details": { "disinfectant": { "text": "Scottsdale uses chlorine to keep treated water disinfected.", "kind": "chlorine", "source_title": "Scottsdale 2026 Water Quality Report", "source_url": "https://www.scottsdaleaz.gov/docs/default-source/scottsdaleaz/water/water-quality/annual-reports/2026-water-quality-report.pdf?sfvrsn=18a67596_1", "evidence_ids": [ "SCOTTS-L-01" ] }, "source_water": { "text": "Scottsdale gets most of its surface water from the Colorado River, plus Salt and Verde River water, deep aquifer wells and recycled water.", "source_title": "Scottsdale 2026 Water Quality Report", "source_url": "https://www.scottsdaleaz.gov/docs/default-source/scottsdaleaz/water/water-quality/annual-reports/2026-water-quality-report.pdf?sfvrsn=18a67596_1", "evidence_ids": [ "SCOTTS-L-02" ] }, "seasonal": { "text": "Depending on the time of year, weather and demand, a home may get water from one source or a mix of sources.", "source_title": "Scottsdale 2026 Water Quality Report", "source_url": "https://www.scottsdaleaz.gov/docs/default-source/scottsdaleaz/water/water-quality/annual-reports/2026-water-quality-report.pdf?sfvrsn=18a67596_1", "evidence_ids": [ "SCOTTS-L-03" ] }, "by_area": { "text": "Scottsdale says hardness varies across the city and publishes a table of it by area in its report.", "source_title": "Scottsdale 2026 Water Quality Report", "source_url": "https://www.scottsdaleaz.gov/docs/default-source/scottsdaleaz/water/water-quality/annual-reports/2026-water-quality-report.pdf?sfvrsn=18a67596_1", "evidence_ids": [ "SCOTTS-L-04" ] } }, "sources_checked_on": "2026-10-26", "site": "https://scottsdalewatersystems.com/", "brand": "Scottsdale Water Systems by My Home Water System", "taking_requests": true }, { "city": "Tucson", "state": "AZ", "slug": "tucson", "hardness_facts": [ { "utility": "Tucson Water", "measure": "Hardness, as Tucson Water describes it", "value_as_published": "\"Hard to very hard\" (no number given)", "period": "Undated document", "source_title": "Tucson Water: Water Quality Parameter Explanation", "source_url": "https://www.tucsonaz.gov/files/sharedassets/public/v/1/city-services/tucson-water/water-quality/parameter-explanation-table.pdf" } ], "published_span_mg_per_l": null, "span_converted_from_grains": false, "usgs_class": null, "usgs_class_source": "https://www.usgs.gov/water-science-school/science/hardness-water", "notes": [ "Tucson Water shows hardness by address on an interactive map that we could not read, and its 2023 and 2025 reports list hardness as monitored without a value." ], "local_details": { "disinfectant": { "text": "Tucson Water keeps a chlorine residual of 0.80 to 1.2 mg/L through its pipes.", "kind": "chlorine", "source_title": "Tucson Water 2025 Consumer Confidence Report", "source_url": "https://www.tucsonaz.gov/files/sharedassets/public/v/1/city-services/tucson-water/water-quality/report-archive/ccr_mainsystem_2025.pdf", "evidence_ids": [ "TUCSON-L-01" ] }, "source_water": { "text": "Most Tucson water is Colorado River water delivered by the Central Arizona Project, soaked into the ground in Avra Valley and at Pima Mine Road and pumped back out, plus groundwater from the Central Well Field.", "source_title": "Tucson Water 2025 Consumer Confidence Report", "source_url": "https://www.tucsonaz.gov/files/sharedassets/public/v/1/city-services/tucson-water/water-quality/report-archive/ccr_mainsystem_2025.pdf", "evidence_ids": [ "TUCSON-L-02" ] }, "seasonal": { "text": "Tucson Water says hardness rises as the share of Central Arizona Project water rises.", "source_title": "Tucson Water hard water page", "source_url": "https://www.tucsonaz.gov/Departments/Water/Water-Quality/Aesthetics/Hard-Water", "evidence_ids": [ "TUCSON-L-03" ] } }, "sources_checked_on": "2026-10-27", "site": "https://tucsonwatersystems.com/", "brand": "Tucson Water Systems by My Home Water System", "taking_requests": false }, { "city": "Los Angeles", "state": "CA", "slug": "los-angeles", "hardness_facts": [ { "utility": "LADWP", "measure": "Total hardness, Los Angeles Aqueduct plant", "value_as_published": "Average 103 mg/L, range 96-117 mg/L", "period": "Calendar year 2025", "source_title": "Drinking Water Quality Report 2025 (LADWP), Table III", "source_url": "https://www.ladwp.com/sites/default/files/2026-07/2026_DWQR_Print_Rev2_Digital-remediated.pdf" }, { "utility": "LADWP", "measure": "Total hardness, northern wells", "value_as_published": "Average 115 mg/L, range 78-151 mg/L", "period": "Calendar year 2025", "source_title": "Drinking Water Quality Report 2025 (LADWP), Table III", "source_url": "https://www.ladwp.com/sites/default/files/2026-07/2026_DWQR_Print_Rev2_Digital-remediated.pdf" }, { "utility": "LADWP", "measure": "Total hardness, southern wells", "value_as_published": "Average 116 mg/L, range 83-159 mg/L", "period": "Calendar year 2025", "source_title": "Drinking Water Quality Report 2025 (LADWP), Table III", "source_url": "https://www.ladwp.com/sites/default/files/2026-07/2026_DWQR_Print_Rev2_Digital-remediated.pdf" }, { "utility": "LADWP", "measure": "Total hardness, MWD Weymouth plant", "value_as_published": "Average 234 mg/L, range 189-280 mg/L", "period": "Calendar year 2025", "source_title": "Drinking Water Quality Report 2025 (LADWP), Table III", "source_url": "https://www.ladwp.com/sites/default/files/2026-07/2026_DWQR_Print_Rev2_Digital-remediated.pdf" }, { "utility": "LADWP", "measure": "Total hardness, MWD Diemer plant", "value_as_published": "Average 236 mg/L, range 191-280 mg/L", "period": "Calendar year 2025", "source_title": "Drinking Water Quality Report 2025 (LADWP), Table III", "source_url": "https://www.ladwp.com/sites/default/files/2026-07/2026_DWQR_Print_Rev2_Digital-remediated.pdf" }, { "utility": "LADWP", "measure": "Total hardness, MWD Jensen plant", "value_as_published": "Average 140 mg/L, range 137-142 mg/L", "period": "Calendar year 2025", "source_title": "Drinking Water Quality Report 2025 (LADWP), Table III", "source_url": "https://www.ladwp.com/sites/default/files/2026-07/2026_DWQR_Print_Rev2_Digital-remediated.pdf" } ], "published_span_mg_per_l": [ 78, 280 ], "span_converted_from_grains": false, "usgs_class": "moderately hard to very hard", "usgs_class_source": "https://www.usgs.gov/water-science-school/science/hardness-water", "notes": [ "In 2025 the Aqueduct supplied 44 percent and Metropolitan Water District water 52 percent.", "LADWP's FAQ gives older 2022 figures by area: about 8.6 grains per gallon in the San Fernando Valley and western Los Angeles, and about 16.3 in eastern Los Angeles and the Harbor." ], "local_details": { "disinfectant": { "text": "LADWP disinfects its drinking water with chloramine.", "kind": "chloramine", "source_title": "LADWP 2026 Drinking Water Quality Report", "source_url": "https://www.ladwp.com/sites/default/files/2026-07/2026_DWQR_Print_Rev2_Digital-remediated.pdf", "evidence_ids": [ "LOSANG-L-01" ] }, "source_water": { "text": "In 2025, 44 percent of LADWP water came from the Los Angeles Aqueduct, 52 percent was bought from the Metropolitan Water District (State Water Project and Colorado River), 1 percent was local groundwater and 3 percent was recycled water.", "source_title": "LADWP 2026 Drinking Water Quality Report", "source_url": "https://www.ladwp.com/sites/default/files/2026-07/2026_DWQR_Print_Rev2_Digital-remediated.pdf", "evidence_ids": [ "LOSANG-L-02" ] }, "by_area": { "text": "LADWP reports by community zone, and says the sources serving a zone can change with operations and supply, so water differs across the city.", "source_title": "LADWP 2026 Drinking Water Quality Report", "source_url": "https://www.ladwp.com/sites/default/files/2026-07/2026_DWQR_Print_Rev2_Digital-remediated.pdf", "evidence_ids": [ "LOSANG-L-03" ] } }, "sources_checked_on": "2026-10-27", "site": "https://losangeleswatersystems.com/", "brand": "Los Angeles Water Systems by My Home Water System", "taking_requests": true }, { "city": "Riverside", "state": "CA", "slug": "riverside", "hardness_facts": [ { "utility": "Riverside Public Utilities", "measure": "Hardness", "value_as_published": "Average 197 mg/L (12 grains per gallon), range 180-210 mg/L", "period": "Calendar year 2025", "source_title": "Riverside Public Utilities 2025 Water Quality Report", "source_url": "https://www.riversideca.gov/utilities/sites/riversideca.gov.utilities/files/pdf/water-quality/2025%20Water%20Quality%20Report.pdf" } ], "published_span_mg_per_l": [ 180, 210 ], "span_converted_from_grains": false, "usgs_class": "hard to very hard", "usgs_class_source": "https://www.usgs.gov/water-science-school/science/hardness-water", "notes": [], "local_details": { "disinfectant": { "text": "Riverside Public Utilities lists chlorine as its disinfectant. The 2025 report does not mention chloramine.", "kind": "chlorine", "source_title": "Riverside Public Utilities 2025 Water Quality Report", "source_url": "https://www.riversideca.gov/utilities/sites/riversideca.gov.utilities/files/pdf/water-quality/2025%20Water%20Quality%20Report.pdf", "evidence_ids": [ "RIVERS-L-01" ] }, "source_water": { "text": "Riverside water is local groundwater from the Bunker Hill and Riverside basins.", "source_title": "Riverside Public Utilities 2025 Water Quality Report", "source_url": "https://www.riversideca.gov/utilities/sites/riversideca.gov.utilities/files/pdf/water-quality/2025%20Water%20Quality%20Report.pdf", "evidence_ids": [ "RIVERS-L-02" ] } }, "sources_checked_on": "2026-10-27", "site": "https://riversidehomewatersystems.com/", "brand": "Riverside Home Water Systems by My Home Water System", "taking_requests": false }, { "city": "San Diego", "state": "CA", "slug": "san-diego", "hardness_facts": [ { "utility": "City of San Diego Public Utilities", "measure": "Total hardness, Alvarado plant", "value_as_published": "Average 237 ppm (13.8 grains per gallon), range 203-270 ppm", "period": "Calendar year 2025", "source_title": "Annual Drinking Water Quality Report (2025 data)", "source_url": "https://www.sandiego.gov/sites/default/files/2026-06/pud-annual-drinking-water-quality-report-2025.pdf" }, { "utility": "City of San Diego Public Utilities", "measure": "Total hardness, Miramar plant", "value_as_published": "Average 242 ppm (14.1 grains per gallon), range 200-285 ppm", "period": "Calendar year 2025", "source_title": "Annual Drinking Water Quality Report (2025 data)", "source_url": "https://www.sandiego.gov/sites/default/files/2026-06/pud-annual-drinking-water-quality-report-2025.pdf" }, { "utility": "City of San Diego Public Utilities", "measure": "Total hardness, Otay plant", "value_as_published": "Average 243 ppm (14.2 grains per gallon), range 201-271 ppm", "period": "Calendar year 2025", "source_title": "Annual Drinking Water Quality Report (2025 data)", "source_url": "https://www.sandiego.gov/sites/default/files/2026-06/pud-annual-drinking-water-quality-report-2025.pdf" }, { "utility": "City of San Diego Public Utilities", "measure": "Total hardness, purchased treated water", "value_as_published": "Average 145 ppm (8.5 grains per gallon), range 54.4-232 ppm", "period": "Calendar year 2025", "source_title": "Annual Drinking Water Quality Report (2025 data)", "source_url": "https://www.sandiego.gov/sites/default/files/2026-06/pud-annual-drinking-water-quality-report-2025.pdf" } ], "published_span_mg_per_l": [ 54.4, 285 ], "span_converted_from_grains": false, "usgs_class": "soft to very hard", "usgs_class_source": "https://www.usgs.gov/water-science-school/science/hardness-water", "notes": [ "Most of the supply is imported from the Colorado River and the State Water Project." ], "local_details": { "disinfectant": { "text": "San Diego uses chloramine to keep water disinfected in the pipes, after ozone or chlorine dioxide treatment at its plants.", "kind": "chloramine", "source_title": "City of San Diego 2025 Annual Drinking Water Quality Report", "source_url": "https://www.sandiego.gov/sites/default/files/2026-06/pud-annual-drinking-water-quality-report-2025.pdf", "evidence_ids": [ "SANDIE-L-01" ] }, "source_water": { "text": "Most San Diego water is imported through the County Water Authority, mainly a Colorado River and State Water Project blend, with local reservoir water, treated at the Alvarado, Miramar and Otay plants.", "source_title": "City of San Diego 2025 Annual Drinking Water Quality Report", "source_url": "https://www.sandiego.gov/sites/default/files/2026-06/pud-annual-drinking-water-quality-report-2025.pdf", "evidence_ids": [ "SANDIE-L-02" ] }, "seasonal": { "text": "The city says the share of water from each source changes through the year.", "source_title": "City of San Diego 2025 Annual Drinking Water Quality Report", "source_url": "https://www.sandiego.gov/sites/default/files/2026-06/pud-annual-drinking-water-quality-report-2025.pdf", "evidence_ids": [ "SANDIE-L-03" ] } }, "sources_checked_on": "2026-10-27", "site": "https://sandiegowatersystems.com/", "brand": "San Diego Water Systems by My Home Water System", "taking_requests": true }, { "city": "San Francisco", "state": "CA", "slug": "san-francisco", "hardness_facts": [ { "utility": "SFPUC", "measure": "Hardness", "value_as_published": "Average 62 ppm, range 8.1-112 ppm", "period": "Calendar year 2025", "source_title": "2025 Annual Water Quality Report (City of San Francisco)", "source_url": "https://www.sfpuc.gov/vi/sites/default/files/accounts-and-services/water-quality/water-quality-en-SF-2025.pdf" } ], "published_span_mg_per_l": [ 8.1, 112 ], "span_converted_from_grains": false, "usgs_class": "soft to moderately hard", "usgs_class_source": "https://www.usgs.gov/water-science-school/science/hardness-water", "notes": [], "local_details": { "disinfectant": { "text": "SFPUC disinfects with ultraviolet light and chlorine and keeps the water disinfected in the pipes with chloramine.", "kind": "chloramine", "source_title": "SFPUC 2025 Water Quality Report", "source_url": "https://www.sfpuc.gov/vi/sites/default/files/accounts-and-services/water-quality/water-quality-en-SF-2025.pdf", "evidence_ids": [ "SANFRA-L-01" ] }, "source_water": { "text": "Hetch Hetchy Reservoir supplies up to 85 percent of San Francisco water each year, with the rest from Bay Area reservoirs and a small amount of local groundwater.", "source_title": "SFPUC 2025 Water Quality Report", "source_url": "https://www.sfpuc.gov/vi/sites/default/files/accounts-and-services/water-quality/water-quality-en-SF-2025.pdf", "evidence_ids": [ "SANFRA-L-02" ] }, "seasonal": { "text": "SFPUC says blending different sources through the year gave varying water quality.", "source_title": "SFPUC 2025 Water Quality Report", "source_url": "https://www.sfpuc.gov/vi/sites/default/files/accounts-and-services/water-quality/water-quality-en-SF-2025.pdf", "evidence_ids": [ "SANFRA-L-03" ] } }, "sources_checked_on": "2026-10-27", "site": "https://sanfranciscowatersystems.com/", "brand": "San Francisco Water Systems by My Home Water System", "taking_requests": false }, { "city": "Denver", "state": "CO", "slug": "denver", "hardness_facts": [ { "utility": "Denver Water", "measure": "Total hardness", "value_as_published": "Average 105,009 ppb, range 55,000-124,000 ppb", "period": "Calendar year 2025", "source_title": "2026 Water Quality Report", "source_url": "https://www.denverwater.org/sites/default/files/water-quality-report-2026.pdf" }, { "utility": "Denver Water", "measure": "Hardness, as Denver Water describes it", "value_as_published": "\"Soft to moderately hard\"", "period": "Undated web page", "source_title": "Denver Water: Water Hardness", "source_url": "https://www.denverwater.org/your-water/water-quality/water-hardness" } ], "published_span_mg_per_l": [ 55, 124 ], "span_converted_from_grains": false, "usgs_class": "soft to hard", "usgs_class_source": "https://www.usgs.gov/water-science-school/science/hardness-water", "notes": [ "Denver Water publishes hardness in parts per billion. 1,000 ppb equals 1 ppm, so its 2025 range is 55 to 124 ppm. Its own description, soft to moderately hard, is milder than the USGS class for the top of that range." ], "local_details": { "disinfectant": { "text": "Denver Water adds chloramine after filtration to keep the water disinfected.", "kind": "chloramine", "source_title": "Denver Water treated water quality summary", "source_url": "https://www.denverwater.org/your-water/water-quality/treated-water-quality-summary", "evidence_ids": [ "DENVER-L-01" ] }, "source_water": { "text": "Denver Water draws on rivers, streams, reservoirs and springs fed by mountain snowmelt, gathered through a north and a south collection system.", "source_title": "Denver Water 2026 Water Quality Report", "source_url": "https://www.denverwater.org/sites/default/files/water-quality-report-2026.pdf", "evidence_ids": [ "DENVER-L-02" ] }, "seasonal": { "text": "Denver Water says its water is slightly harder in winter, when waterways and reservoirs freeze, and softer from late spring through fall, when runoff dilutes the minerals.", "source_title": "Denver Water water hardness page", "source_url": "https://www.denverwater.org/your-water/water-quality/water-hardness", "evidence_ids": [ "DENVER-L-03" ] } }, "sources_checked_on": "2026-10-27", "site": "https://denverwatersystems.com/", "brand": "Denver Water Systems by My Home Water System", "taking_requests": false }, { "city": "Washington", "state": "DC", "slug": "washington-dc", "hardness_facts": [ { "utility": "DC Water", "measure": "Total hardness", "value_as_published": "Average 139 ppm (8 grains per gallon), range 84-194 ppm", "period": "Calendar year 2025", "source_title": "2026 Drinking Water Quality Report (DC Water), summarizing 2025 water quality test results", "source_url": "https://www.dcwater.com/waterreport" } ], "published_span_mg_per_l": [ 84, 194 ], "span_converted_from_grains": false, "usgs_class": "moderately hard to very hard", "usgs_class_source": "https://www.usgs.gov/water-science-school/science/hardness-water", "notes": [], "local_details": { "disinfectant": { "text": "For most of the year, the Washington Aqueduct uses chloramine to keep DC water disinfected.", "kind": "chloramine", "source_title": "DC Water 2026 Drinking Water Quality Report", "source_url": "https://www.dcwater.com/waterreport", "evidence_ids": [ "WASHIN-L-01" ] }, "source_water": { "text": "DC water comes from the Potomac River, treated by the Washington Aqueduct and bought by DC Water.", "source_title": "DC Water 2026 Drinking Water Quality Report", "source_url": "https://www.dcwater.com/waterreport", "evidence_ids": [ "WASHIN-L-02" ] }, "seasonal": { "text": "For a short time each spring, the Aqueduct switches from chloramine to chlorine only.", "source_title": "DC Water 2026 Drinking Water Quality Report", "source_url": "https://www.dcwater.com/waterreport", "evidence_ids": [ "WASHIN-L-03" ] } }, "sources_checked_on": "2026-10-27", "site": "https://dcwatersystems.com/", "brand": "DC Water Systems by My Home Water System", "taking_requests": false }, { "city": "Jacksonville", "state": "FL", "slug": "jacksonville", "hardness_facts": [], "published_span_mg_per_l": null, "span_converted_from_grains": false, "usgs_class": null, "usgs_class_source": "https://www.usgs.gov/water-science-school/science/hardness-water", "notes": [ "JEA's website stopped us with a bot check, so we have not read its water quality report and do not show a figure.", "The nearest published measure we found is a 1977 U.S. Geological Survey report that put Floridan aquifer water in metropolitan Jacksonville at about 250 to more than 300 mg/L hardness. That is untreated groundwater, not JEA tap water." ], "local_details": {}, "sources_checked_on": "2026-10-27", "site": "https://jacksonvillewatersystems.com/", "brand": "Jacksonville Water Systems by My Home Water System", "taking_requests": false }, { "city": "Miami", "state": "FL", "slug": "miami", "hardness_facts": [], "published_span_mg_per_l": null, "span_converted_from_grains": false, "usgs_class": null, "usgs_class_source": "https://www.usgs.gov/water-science-school/science/hardness-water", "notes": [ "None of Miami-Dade's water quality reports we read (2003, 2013, 2014, 2015, 2023 and 2025) publishes a hardness figure.", "The U.S. Geological Survey Ground Water Atlas describes Biscayne Aquifer water as hard, with no number. That describes untreated aquifer water, not tap water." ], "local_details": { "disinfectant": { "text": "The Miami-Dade main system, which serves the City of Miami, keeps the water disinfected with chloramine.", "kind": "chloramine", "source_title": "Miami-Dade WASD 2025 Water Quality Report", "source_url": "https://www.miamidade.gov/resources/water/documents/2025-water-quality-report.pdf", "evidence_ids": [ "MIAMI-L-01" ] }, "source_water": { "text": "Most Miami-Dade water comes from the Biscayne Aquifer, treated at the Hialeah, John E. Preston and Alexander Orr Jr. plants. The Hialeah reverse osmosis plant draws from the deeper Upper Floridan Aquifer.", "source_title": "Miami-Dade WASD 2025 Water Quality Report", "source_url": "https://www.miamidade.gov/resources/water/documents/2025-water-quality-report.pdf", "evidence_ids": [ "MIAMI-L-02" ] }, "softening": { "text": "Partly. Water from the Alexander Orr Jr. plant gets lime treatment to reduce hardness before it is disinfected and filtered.", "source_title": "Miami-Dade WASD 2025 Water Quality Report", "source_url": "https://www.miamidade.gov/resources/water/documents/2025-water-quality-report.pdf", "evidence_ids": [ "MIAMI-L-03" ] }, "by_area": { "text": "The Orr plant generally serves areas south of SW 8 Street, and the Hialeah and Preston plants serve areas north of it.", "source_title": "Miami-Dade WASD 2025 Water Quality Report", "source_url": "https://www.miamidade.gov/resources/water/documents/2025-water-quality-report.pdf", "evidence_ids": [ "MIAMI-L-04" ] } }, "sources_checked_on": "2026-10-27", "site": "https://miamihomewatersystems.com/", "brand": "Miami Home Water Systems by My Home Water System", "taking_requests": false }, { "city": "Orlando", "state": "FL", "slug": "orlando", "hardness_facts": [ { "utility": "OUC", "measure": "Total hardness", "value_as_published": "Average 129 ppm (7 grains per gallon)", "period": "Undated web page", "source_title": "Water Services (OUC)", "source_url": "https://www.ouc.com/about/water-services/" } ], "published_span_mg_per_l": [ 129, 129 ], "span_converted_from_grains": false, "usgs_class": "hard", "usgs_class_source": "https://www.usgs.gov/water-science-school/science/hardness-water", "notes": [], "local_details": { "disinfectant": { "text": "OUC treats with ozone first, which lets it use less chlorine. It lists chlorine at an average 1.0 ppm and says it does not use chloramine.", "kind": "chlorine", "source_title": "OUC water services page", "source_url": "https://www.ouc.com/about/water-services/", "evidence_ids": [ "ORLAND-L-01" ] }, "source_water": { "text": "OUC water comes from the Lower Floridan Aquifer.", "source_title": "OUC water services page", "source_url": "https://www.ouc.com/about/water-services/", "evidence_ids": [ "ORLAND-L-02" ] }, "service": { "text": "OUC serves the City of Orlando and parts of Orange County.", "source_title": "OUC water services page", "source_url": "https://www.ouc.com/about/water-services/", "evidence_ids": [ "ORLAND-L-03" ] } }, "sources_checked_on": "2026-10-27", "site": "https://orlandowatersystems.com/", "brand": "Orlando Water Systems by My Home Water System", "taking_requests": false }, { "city": "Tampa", "state": "FL", "slug": "tampa", "hardness_facts": [ { "utility": "Tampa Water Department", "measure": "Total hardness", "value_as_published": "Average 185 mg/L (10.8 grains per gallon)", "period": "Calendar year 2024", "source_title": "2024 Water Quality Report (City of Tampa, published 2025)", "source_url": "https://www.tampa.gov/sites/default/files/document/2025/2024-water-quality-report-ada-compliant.pdf" }, { "utility": "Tampa Water Department", "measure": "Hardness through the year", "value_as_published": "About 140-300 ppm (8-17 grains per gallon)", "period": "Undated document", "source_title": "Understanding Water Hardness (City of Tampa)", "source_url": "https://www.tampa.gov/sites/default/files/document/2026/understanding-water-hardness.pdf" } ], "published_span_mg_per_l": [ 140, 300 ], "span_converted_from_grains": false, "usgs_class": "hard to very hard", "usgs_class_source": "https://www.usgs.gov/water-science-school/science/hardness-water", "notes": [ "The Tampa Water Department adds monochloramine (chlorine and ammonia) before water leaves the plant.", "The city says hardness changes with the seasons. It also uses stored aquifer water and buys water from Tampa Bay Water when needed." ], "local_details": { "disinfectant": { "text": "Tampa adds ammonia to make chloramine so the water stays disinfected through the pipes.", "kind": "chloramine", "source_title": "Tampa 2024 Water Quality Report", "source_url": "https://www.tampa.gov/sites/default/files/document/2025/2024-water-quality-report-ada-compliant.pdf", "evidence_ids": [ "TAMPA-L-01" ] }, "source_water": { "text": "Tampa relies mainly on the Hillsborough River, plus treated water stored in aquifer wells and a small share bought from Tampa Bay Water (2.5 percent in 2024).", "source_title": "Tampa 2024 Water Quality Report", "source_url": "https://www.tampa.gov/sites/default/files/document/2025/2024-water-quality-report-ada-compliant.pdf", "evidence_ids": [ "TAMPA-L-02" ] }, "seasonal": { "text": "The city says hardness is lower in the wet season and higher in the dry season.", "source_title": "City of Tampa, Understanding Water Hardness", "source_url": "https://www.tampa.gov/sites/default/files/document/2026/understanding-water-hardness.pdf", "evidence_ids": [ "TAMPA-L-03" ] } }, "sources_checked_on": "2026-10-27", "site": "https://tampabaywatersystems.com/", "brand": "Tampa Bay Water Systems by My Home Water System", "taking_requests": false }, { "city": "Atlanta", "state": "GA", "slug": "atlanta", "hardness_facts": [], "published_span_mg_per_l": null, "span_converted_from_grains": false, "usgs_class": null, "usgs_class_source": "https://www.usgs.gov/water-science-school/science/hardness-water", "notes": [ "None of the city's water quality reports we read (2006, 2013, 2017 through 2022 and 2025) publishes a hardness figure.", "The nearest published measure we found is a 1951 U.S. Geological Survey study that put Chattahoochee River water at Atlanta under 22 parts per million total hardness in 1937-38 samples. That is untreated river water from decades ago, not tap water, so we do not use it as a figure for Atlanta homes." ], "local_details": { "disinfectant": { "text": "Atlanta lists chlorine as the additive that controls microbes, with a highest monthly average of 1.13 ppm in 2025.", "kind": "chlorine", "source_title": "City of Atlanta 2025 Water Quality Report", "source_url": "https://drive.google.com/file/d/11kz5ciFgXn1hLVe_UzxMFVLw4z3LldlY/view?usp=share_link", "evidence_ids": [ "ATLANT-L-01" ] }, "source_water": { "text": "Atlanta draws all of its water from the Chattahoochee River. The Chattahoochee and Hemphill plants make about 75 percent of it, and the jointly owned Atlanta-Fulton County plant serves the northeast part of the system.", "source_title": "City of Atlanta 2025 Water Quality Report", "source_url": "https://drive.google.com/file/d/11kz5ciFgXn1hLVe_UzxMFVLw4z3LldlY/view?usp=share_link", "evidence_ids": [ "ATLANT-L-02" ] } }, "sources_checked_on": "2026-10-27", "site": "https://atlantawatersystems.com/", "brand": "Atlanta Water Systems by My Home Water System", "taking_requests": false }, { "city": "Chicago", "state": "IL", "slug": "chicago", "hardness_facts": [ { "utility": "Chicago Department of Water Management", "measure": "Hardness as CaCO3, quarterly samples at both plants", "value_as_published": "129 to 158 mg/L", "period": "Three 2014 quarterly samplings (March, June and August 2014)", "source_title": "Chicago 2014 Comprehensive Chemical Analysis", "source_url": "https://www.chicago.gov/content/dam/city/depts/water/WaterQltyResultsNRpts/ccReports/cca14.pdf" } ], "published_span_mg_per_l": [ 129, 158 ], "span_converted_from_grains": false, "usgs_class": "hard", "usgs_class_source": "https://www.usgs.gov/water-science-school/science/hardness-water", "notes": [ "The city's water quality reports for 2017 and 2021 through 2024 list no hardness figure, and its newer chemical analyses would not load for us, so the 2014 analysis is the newest published number we found.", "The 2014 figures cover raw and treated samples from both plants together." ], "local_details": { "disinfectant": { "text": "Chicago lists chlorine as its drinking water disinfectant.", "kind": "chlorine", "source_title": "Chicago 2024 Water Quality Report", "source_url": "https://www.chicago.gov/content/dam/city/depts/water/ConsumerConfidenceReports/2024_WaterQuality%20Report_CCR.pdf", "evidence_ids": [ "CHICAG-L-01" ] }, "source_water": { "text": "Chicago draws Lake Michigan water through offshore intakes to two plants: Jardine serves the north side and Sawyer the south side.", "source_title": "Chicago 2024 Water Quality Report", "source_url": "https://www.chicago.gov/content/dam/city/depts/water/ConsumerConfidenceReports/2024_WaterQuality%20Report_CCR.pdf", "evidence_ids": [ "CHICAG-L-02" ] } }, "sources_checked_on": "2026-10-27", "site": "https://chicagowatersystems.com/", "brand": "Chicago Water Systems by My Home Water System", "taking_requests": true }, { "city": "Indianapolis", "state": "IN", "slug": "indianapolis", "hardness_facts": [ { "utility": "Citizens Energy Group", "measure": "Hardness", "value_as_published": "Average 317 ppm (19 grains per gallon), range 148-460 ppm", "period": "Calendar year 2025", "source_title": "2025 Drinking Water Report (Citizens Energy Group, 2025 Water Quality Report)", "source_url": "https://info.citizensenergygroup.com/hubfs/site/water/2025%20Citizens%20Water%20Quality%20Report.pdf" } ], "published_span_mg_per_l": [ 148, 460 ], "span_converted_from_grains": false, "usgs_class": "hard to very hard", "usgs_class_source": "https://www.usgs.gov/water-science-school/science/hardness-water", "notes": [ "The same 2025 report also says hardness averages 320 mg/L in its text." ], "local_details": { "disinfectant": { "text": "Citizens Energy Group adds chlorine and a small amount of ammonia, and lists chloramine as the additive that controls microbes.", "kind": "chloramine", "source_title": "Citizens Energy Group 2025 Water Quality Report", "source_url": "https://info.citizensenergygroup.com/hubfs/site/water/2025%20Citizens%20Water%20Quality%20Report.pdf", "evidence_ids": [ "INDIAN-L-01" ] }, "source_water": { "text": "Most Indianapolis water is surface water from the West Fork of the White River, Fall Creek and Eagle Creek Reservoir, with Morse and Geist reservoirs, plus groundwater from wells.", "source_title": "Citizens Energy Group 2025 Water Quality Report", "source_url": "https://info.citizensenergygroup.com/hubfs/site/water/2025%20Citizens%20Water%20Quality%20Report.pdf", "evidence_ids": [ "INDIAN-L-02" ] }, "by_area": { "text": "Citizens says hardness varies with the source water feeding each treatment plant, so it can differ by where you live.", "source_title": "Citizens Energy Group 2025 Water Quality Report", "source_url": "https://info.citizensenergygroup.com/hubfs/site/water/2025%20Citizens%20Water%20Quality%20Report.pdf", "evidence_ids": [ "INDIAN-L-03" ] } }, "sources_checked_on": "2026-10-27", "site": "https://indianapoliswatersystems.com/", "brand": "Indianapolis Water Systems by My Home Water System", "taking_requests": true }, { "city": "Boston", "state": "MA", "slug": "boston", "hardness_facts": [ { "utility": "MWRA (for Boston Water and Sewer Commission)", "measure": "Typical total hardness", "value_as_published": "Approximately 16 mg/L, or 1 grain per gallon", "period": "Undated web page", "source_title": "Frequently Asked Questions About Drinking Water (MWRA)", "source_url": "https://www.mwra.com/your-water-system/drinking-water-quality/frequently-asked-questions-about-mwra-tap-water" }, { "utility": "MWRA (for Boston Water and Sewer Commission)", "measure": "Total hardness, monthly reading", "value_as_published": "14.3 mg/L at the Carroll Water Treatment Plant", "period": "July 2026 sampling", "source_title": "Water Quality Update: An Analysis of July 2026 Sampling Data (MWRA)", "source_url": "https://www.mwra.com/media/file/wq-update-072026" } ], "published_span_mg_per_l": [ 14.3, 20 ], "span_converted_from_grains": false, "usgs_class": "soft", "usgs_class_source": "https://www.usgs.gov/water-science-school/science/hardness-water", "notes": [ "The MWRA's July 2026 update describes hardness as about 15 to 20 mg/L, or about 1 grain per gallon." ], "local_details": { "disinfectant": { "text": "MWRA, which supplies Boston, disinfects with monochloramine, a compound of chlorine and ammonia.", "kind": "chloramine", "source_title": "MWRA 2025 Annual Water Quality Test Results", "source_url": "https://www.mwra.com/node/8620", "evidence_ids": [ "BOSTON-L-01" ] }, "source_water": { "text": "Boston water comes from MWRA's Quabbin and Wachusett reservoirs in central Massachusetts and is delivered by the Boston Water and Sewer Commission.", "source_title": "MWRA 2025 Annual Water Quality Test Results", "source_url": "https://www.mwra.com/node/8620", "evidence_ids": [ "BOSTON-L-02" ] }, "seasonal": { "text": "MWRA says a chlorine smell is more likely in summer, when water is warmer, and that algae in its reservoirs can cause an earthy taste in spring and fall.", "source_title": "MWRA tap water FAQ", "source_url": "https://www.mwra.com/your-water-system/drinking-water-quality/frequently-asked-questions-about-mwra-tap-water", "evidence_ids": [ "BOSTON-L-03" ] } }, "sources_checked_on": "2026-10-27", "site": "https://bostonwatersystems.com/", "brand": "Boston Water Systems by My Home Water System", "taking_requests": false }, { "city": "Baltimore", "state": "MD", "slug": "baltimore", "hardness_facts": [ { "utility": "Baltimore City DPW (Montebello laboratory)", "measure": "Hardness, annual average of monthly results", "value_as_published": "114 mg/L (monthly range 109-120)", "period": "Calendar year 2022", "source_title": "Montebello Water Quality Laboratory Mineral Analyses 2022", "source_url": "https://publicworks.baltimorecity.gov/files/min-anal-2022pdf" }, { "utility": "Baltimore City DPW (Ashburton laboratory)", "measure": "Hardness, annual average of monthly results", "value_as_published": "80 (monthly range 76-84; the form prints no unit)", "period": "Calendar year 2022", "source_title": "Ashburton Water Quality Laboratory Mineral Analyses 2022", "source_url": "https://publicworks.baltimorecity.gov/files/min-anal-2022-ashburton-labpdf" } ], "published_span_mg_per_l": [ 109, 120 ], "span_converted_from_grains": false, "usgs_class": "moderately hard", "usgs_class_source": "https://www.usgs.gov/water-science-school/science/hardness-water", "notes": [ "The city's 2023, 2024 and 2025 water quality reports list no hardness figure, and we found no mineral analyses newer than 2022.", "The scale on this page uses the Montebello figures only, because the Ashburton form does not print a unit." ], "local_details": { "disinfectant": { "text": "Baltimore lists chlorine as the additive that disinfects its supply.", "kind": "chlorine", "source_title": "Baltimore City 2025 Water Quality Report", "source_url": "https://s3.amazonaws.com/baltimorecity.gov.if-us-east-1/s3fs-public/2026-07/2025%20Baltimore%20City%20Water%20Quality%20Report.pdf", "evidence_ids": [ "BALTIM-L-01" ] }, "source_water": { "text": "Baltimore water is rain and snowmelt stored in the Liberty, Loch Raven and Prettyboy reservoirs and treated at the Ashburton and Montebello plants. The Susquehanna River is used only in severe drought.", "source_title": "Baltimore City 2025 Water Quality Report", "source_url": "https://s3.amazonaws.com/baltimorecity.gov.if-us-east-1/s3fs-public/2026-07/2025%20Baltimore%20City%20Water%20Quality%20Report.pdf", "evidence_ids": [ "BALTIM-L-02" ] } }, "sources_checked_on": "2026-10-27", "site": "https://baltimorewatersystems.com/", "brand": "Baltimore Water Systems by My Home Water System", "taking_requests": false }, { "city": "Detroit", "state": "MI", "slug": "detroit", "hardness_facts": [ { "utility": "Detroit Water and Sewerage Department", "measure": "Total hardness", "value_as_published": "Average 107 ppm, range 96-142 ppm", "period": "Calendar year 2025", "source_title": "Detroit Water Quality Report, 2025 Results (DWSD - WQR - 2025 - Final)", "source_url": "https://detroitmi.gov/sites/detroitmi.localhost/files/2026-06/DWSD%20-%20WQR%20-%202025%20-%20Final%20-1.pdf" } ], "published_span_mg_per_l": [ 96, 142 ], "span_converted_from_grains": false, "usgs_class": "moderately hard to hard", "usgs_class_source": "https://www.usgs.gov/water-science-school/science/hardness-water", "notes": [], "local_details": { "disinfectant": { "text": "The Detroit report lists a chlorine residual added to control microbes, ranging 0.59 to 1.08 ppm in 2025. It does not mention chloramine.", "kind": "chlorine", "source_title": "DWSD 2025 Water Quality Report", "source_url": "https://detroitmi.gov/sites/detroitmi.localhost/files/2026-06/DWSD%20-%20WQR%20-%202025%20-%20Final%20-1.pdf", "evidence_ids": [ "DETROI-L-01" ] }, "source_water": { "text": "Detroit homes get Detroit River water treated at four Great Lakes Water Authority plants.", "source_title": "DWSD 2025 Water Quality Report", "source_url": "https://detroitmi.gov/sites/detroitmi.localhost/files/2026-06/DWSD%20-%20WQR%20-%202025%20-%20Final%20-1.pdf", "evidence_ids": [ "DETROI-L-02" ] }, "service": { "text": "The Great Lakes Water Authority treats the water and moves it to the city, and the Detroit Water and Sewerage Department delivers it to neighborhoods.", "source_title": "DWSD 2025 Water Quality Report", "source_url": "https://detroitmi.gov/sites/detroitmi.localhost/files/2026-06/DWSD%20-%20WQR%20-%202025%20-%20Final%20-1.pdf", "evidence_ids": [ "DETROI-L-03" ] } }, "sources_checked_on": "2026-10-27", "site": "https://detroitwatersystems.com/", "brand": "Detroit Water Systems by My Home Water System", "taking_requests": false }, { "city": "Minneapolis", "state": "MN", "slug": "minneapolis", "hardness_facts": [ { "utility": "Minneapolis Water Treatment and Distribution", "measure": "Total hardness, plant effluent", "value_as_published": "Average 94 ppm, range 80-113 ppm", "period": "Calendar year 2025", "source_title": "Plant Effluent Water Analysis, Record of data for 2025", "source_url": "https://www.minneapolismn.gov/media/-www-content-assets/documents/2025-Record-of-Data-on-new-ltrhead.pdf" } ], "published_span_mg_per_l": [ 80, 113 ], "span_converted_from_grains": false, "usgs_class": "moderately hard", "usgs_class_source": "https://www.usgs.gov/water-science-school/science/hardness-water", "notes": [ "Minneapolis lists chloramine in its distribution system." ], "local_details": { "disinfectant": { "text": "Minneapolis disinfects with chlorine and lists a chloramine residual in its 2025 water data.", "kind": "chloramine", "source_title": "Minneapolis 2025 Record of Data", "source_url": "https://www.minneapolismn.gov/media/-www-content-assets/documents/2025-Record-of-Data-on-new-ltrhead.pdf", "evidence_ids": [ "MINNEA-L-01" ] }, "source_water": { "text": "Minneapolis water comes from the Mississippi River.", "source_title": "Minneapolis 2025 Consumer Confidence Report", "source_url": "https://www.minneapolismn.gov/media/-www-content-assets/documents/2025-CCR-Revised-%282%29.pdf", "evidence_ids": [ "MINNEA-L-02" ] }, "softening": { "text": "Yes. The city says its treatment removes 65,000 pounds of hardness from the water each day.", "source_title": "Minneapolis water treatment and delivery page", "source_url": "https://www.minneapolismn.gov/government/departments/public-works/water-treatment-distribution/treatment-delivery/", "evidence_ids": [ "MINNEA-L-03" ] } }, "sources_checked_on": "2026-10-27", "site": "https://minneapoliswatersystems.com/", "brand": "Minneapolis Water Systems by My Home Water System", "taking_requests": false }, { "city": "St. Louis", "state": "MO", "slug": "st-louis", "hardness_facts": [ { "utility": "City of St. Louis Water Division", "measure": "Total hardness", "value_as_published": "Average 129 ppm, range 80-206 ppm", "period": "Calendar year 2025", "source_title": "ST. LOUIS CITY WATER - A HISTORY OF EXCELLENCE (2025 Consumer Confidence Report)", "source_url": "https://www.stlwater.com/ccr.pdf" } ], "published_span_mg_per_l": [ 80, 206 ], "span_converted_from_grains": false, "usgs_class": "moderately hard to very hard", "usgs_class_source": "https://www.usgs.gov/water-science-school/science/hardness-water", "notes": [], "local_details": { "disinfectant": { "text": "The St. Louis report lists chloramine as a treatment additive, at 1.67 to 3.46 ppm in 2025.", "kind": "chloramine", "source_title": "St. Louis Water Division Consumer Confidence Report", "source_url": "https://www.stlwater.com/ccr.pdf", "evidence_ids": [ "STLOUI-L-01" ] }, "source_water": { "text": "The Chain of Rocks plant draws from the Mississippi River and the Howard Bend plant from the Missouri River.", "source_title": "St. Louis Water Division Consumer Confidence Report", "source_url": "https://www.stlwater.com/ccr.pdf", "evidence_ids": [ "STLOUI-L-02" ] }, "softening": { "text": "Yes. The city report lists precipitative softening as part of treatment.", "source_title": "St. Louis Water Division Consumer Confidence Report", "source_url": "https://www.stlwater.com/ccr.pdf", "evidence_ids": [ "STLOUI-L-03" ] } }, "sources_checked_on": "2026-10-27", "site": "https://stlouiswatersystems.com/", "brand": "St. Louis Water Systems by My Home Water System", "taking_requests": false }, { "city": "Kansas City", "state": "MO/KS", "slug": "kansas-city", "hardness_facts": [ { "utility": "BPU (Kansas City, KS)", "measure": "Total hardness", "value_as_published": "280 ppm (16.4 grains per gallon)", "period": "Jan.-Dec. 2025", "source_title": "BPU 2026 Water Quality Report", "source_url": "https://bpu.com/wp-content/uploads/2026/08/2026-Water-Quality-Report-FINAL-newformat.pdf" }, { "utility": "WaterOne (Johnson County, KS)", "measure": "Total hardness", "value_as_published": "Average 135 ppm, range 110-157 ppm", "period": "Calendar year 2025", "source_title": "WaterOne Water Quality Report 2026", "source_url": "https://www.waterone.org/ArchiveCenter/ViewFile/Item/177" }, { "utility": "Independence, MO", "measure": "Total hardness", "value_as_published": "123 mg/L as calcium carbonate (single sample)", "period": "Sampled May 6, 2024", "source_title": "Independence 2025 Annual Water Quality Report", "source_url": "https://www.independencemo.gov/sites/default/files/2026-06/2025%20CCR_Draft%20Final.pdf" }, { "utility": "KC Water (Kansas City, MO)", "measure": "Average hardness", "value_as_published": "100 mg/L (5-6 grains per gallon)", "period": "Undated web page", "source_title": "KC Water water quality topics", "source_url": "https://www.kcwater.us/water-quality/water-quality-topics/" } ], "published_span_mg_per_l": [ 100, 280 ], "span_converted_from_grains": false, "usgs_class": "moderately hard to very hard", "usgs_class_source": "https://www.usgs.gov/water-science-school/science/hardness-water", "notes": [ "KC Water's figures do not agree across its own documents: an undated web page gives an average of 100 mg/L, its 2022 report gives a range of 84.6-136 ppm for 2021, and its latest report does not list hardness for its own supply." ], "local_details": { "disinfectant": { "text": "It depends on the utility. WaterOne, BPU and Independence use chloramine, and the newest KC Water statement we found, in its 2022 report, says chlorine is added for disinfection.", "kind": "varies", "source_title": "KC Water 2022 Water Quality Report", "source_url": "https://www.kcwater.us/wp-content/uploads/2022/05/2022-Water-Quality-Report_web.pdf", "evidence_ids": [ "KANSAS-L-01" ] }, "source_water": { "text": "KC Water draws mainly from the Missouri River plus nearby wells. BPU and Independence also draw on the Missouri River and its alluvial aquifer, and WaterOne uses the Kansas and Missouri rivers and wells.", "source_title": "KC Water 2022 Water Quality Report", "source_url": "https://www.kcwater.us/wp-content/uploads/2022/05/2022-Water-Quality-Report_web.pdf", "evidence_ids": [ "KANSAS-L-02" ] }, "softening": { "text": "At least in part. KC Water adds lime at its plant for softening and to improve taste and odor.", "source_title": "KC Water 2022 Water Quality Report", "source_url": "https://www.kcwater.us/wp-content/uploads/2022/05/2022-Water-Quality-Report_web.pdf", "evidence_ids": [ "KANSAS-L-03" ] }, "service": { "text": "Four utilities serve the area. KC Water serves Kansas City, Missouri, BPU serves Kansas City, Kansas, Independence serves Independence, Missouri, and WaterOne serves 17 Johnson County cities, including Overland Park, Lenexa, Shawnee, Leawood and Prairie Village, and parts of Olathe and De Soto.", "source_title": "WaterOne service area page", "source_url": "https://waterone.org/344/WaterOne-Service-Area", "evidence_ids": [ "KANSAS-L-04" ] } }, "sources_checked_on": "2026-10-26", "site": "https://kcwatersystems.com/", "brand": "KC Water Systems by My Home Water System", "taking_requests": true }, { "city": "Charlotte", "state": "NC", "slug": "charlotte", "hardness_facts": [ { "utility": "Charlotte Water", "measure": "Total hardness", "value_as_published": "Average 32 ppm, range 27-35 ppm", "period": "Calendar year 2025", "source_title": "2025 Annual Drinking Water Quality Report (Consumer Confidence Report 2025 - Charlotte Water)", "source_url": "https://www.charlottenc.gov/files/sharedassets/cltwater/v/3/documents/water-quality/ccr/current-consumer-confidence-report.pdf" } ], "published_span_mg_per_l": [ 27, 35 ], "span_converted_from_grains": false, "usgs_class": "soft", "usgs_class_source": "https://www.usgs.gov/water-science-school/science/hardness-water", "notes": [ "A single September 2026 sample at the Franklin plant, posted on Charlotte Water's site, read 39 ppm." ], "local_details": { "disinfectant": { "text": "Charlotte Water adds chlorine to prevent bacterial growth.", "kind": "chlorine", "source_title": "Charlotte Water 2025 Annual Drinking Water Quality Report", "source_url": "https://www.charlottenc.gov/files/sharedassets/cltwater/v/3/documents/water-quality/ccr/current-consumer-confidence-report.pdf", "evidence_ids": [ "CHARLO-L-01" ] }, "source_water": { "text": "Charlotte water comes from Mountain Island Lake and Lake Norman on the Catawba River.", "source_title": "Charlotte Water 2025 Annual Drinking Water Quality Report", "source_url": "https://www.charlottenc.gov/files/sharedassets/cltwater/v/3/documents/water-quality/ccr/current-consumer-confidence-report.pdf", "evidence_ids": [ "CHARLO-L-02" ] } }, "sources_checked_on": "2026-10-27", "site": "https://charlottewatersystems.com/", "brand": "Charlotte Water Systems by My Home Water System", "taking_requests": false }, { "city": "Jersey City", "state": "NJ", "slug": "jersey-city", "hardness_facts": [ { "utility": "Veolia Jersey City", "measure": "Hardness (as calcium carbonate)", "value_as_published": "Range 62-103 ppm", "period": "Calendar year 2022", "source_title": "2022 Annual Drinking Water Quality Report (Veolia Jersey City, issued April 2023)", "source_url": "https://jcmua.com/wp-content/uploads/2024/04/Veolia_Jersey_City_CCR-2022_data_Locked.pdf" } ], "published_span_mg_per_l": [ 62, 103 ], "span_converted_from_grains": false, "usgs_class": "moderately hard", "usgs_class_source": "https://www.usgs.gov/water-science-school/science/hardness-water", "notes": [ "The 2022 report says chlorine is added to disinfect the water.", "The same report lists sodium at 38 to 69 ppm, above New Jersey's recommended upper limit of 50 ppm.", "This is the newest Jersey City report we could read. A 2023 report is posted on Veolia's site, which does not allow automated reading, so it is not used here." ], "local_details": { "disinfectant": { "text": "Jersey City water gets a small amount of chlorine to disinfect it.", "kind": "chlorine", "source_title": "Veolia Jersey City Consumer Confidence Report (2022 data)", "source_url": "https://jcmua.com/wp-content/uploads/2024/04/Veolia_Jersey_City_CCR-2022_data_Locked.pdf", "evidence_ids": [ "JERSEY-L-01" ] }, "source_water": { "text": "Jersey City water comes from the Jersey City Reservoir at Boonton and the Split Rock Reservoir in Rockaway Township, treated at the Boonton plant.", "source_title": "Veolia Jersey City Consumer Confidence Report (2022 data)", "source_url": "https://jcmua.com/wp-content/uploads/2024/04/Veolia_Jersey_City_CCR-2022_data_Locked.pdf", "evidence_ids": [ "JERSEY-L-02" ] }, "seasonal": { "text": "During maintenance on the plant, aqueduct or mains, Jersey City may receive water from the North Jersey District Water Supply Commission instead.", "source_title": "Veolia Jersey City Consumer Confidence Report (2022 data)", "source_url": "https://jcmua.com/wp-content/uploads/2024/04/Veolia_Jersey_City_CCR-2022_data_Locked.pdf", "evidence_ids": [ "JERSEY-L-03" ] } }, "sources_checked_on": "2026-10-27", "site": "https://jerseywatersystems.com/", "brand": "Jersey Water Systems by My Home Water System", "taking_requests": false }, { "city": "Henderson", "state": "NV", "slug": "henderson", "hardness_facts": [ { "utility": "City of Henderson", "measure": "Hardness", "value_as_published": "Typically 304 parts per million (18 grains per gallon)", "period": "2026 report (2025 data)", "source_title": "City of Henderson Water Quality Report", "source_url": "https://www.cityofhenderson.com/government/departments/utility-services/water-quality/water-quality-report" } ], "published_span_mg_per_l": [ 304, 304 ], "span_converted_from_grains": false, "usgs_class": "very hard", "usgs_class_source": "https://www.usgs.gov/water-science-school/science/hardness-water", "notes": [ "The city describes its water as very hard and suggests setting a softener between 16 and 19 grains per gallon.", "Henderson's 2025 free chlorine residual averaged 0.82 ppm." ], "local_details": { "disinfectant": { "text": "Henderson lists a free chlorine residual in its water report.", "kind": "chlorine", "source_title": "Henderson 2026 Water Quality Report", "source_url": "https://www.cityofhenderson.com/home/showpublisheddocument/18097/639154026931400000", "evidence_ids": [ "HENDER-L-01" ] }, "source_water": { "text": "All Henderson water comes from the Colorado River at Lake Mead, treated by the Southern Nevada Water Authority.", "source_title": "City of Henderson water source document", "source_url": "https://www.cityofhenderson.com/home/showpublisheddocument/18284/639184439008070000", "evidence_ids": [ "HENDER-L-02" ] } }, "sources_checked_on": "2026-10-26", "site": "https://hendersonwatersystems.com/", "brand": "Henderson Water Systems by My Home Water System", "taking_requests": true }, { "city": "Las Vegas", "state": "NV", "slug": "las-vegas", "hardness_facts": [ { "utility": "Las Vegas Valley Water District", "measure": "Hardness", "value_as_published": "280 parts per million (16 grains per gallon)", "period": "Calendar year 2025", "source_title": "LVVWD 2026 Water Quality Report", "source_url": "https://www.lvvwd.com/assets/pdf/water-quality-report-las-vegas-valley-current.pdf" } ], "published_span_mg_per_l": [ 280, 280 ], "span_converted_from_grains": false, "usgs_class": "very hard", "usgs_class_source": "https://www.usgs.gov/water-science-school/science/hardness-water", "notes": [ "About 90 percent of the water comes from Lake Mead on the Colorado River and about 10 percent from deep groundwater wells.", "The district disinfects with chlorine. Its 2025 free chlorine residual averaged 0.99 ppm.", "One section of the district's water quality FAQ page gives 291 ppm (17 grains per gallon). The current annual report gives 280 ppm." ], "local_details": { "disinfectant": { "text": "Chlorine is added as water leaves the treatment plants to protect it on the way to the tap.", "kind": "chlorine", "source_title": "Las Vegas Valley Water District 2026 Water Quality Report", "source_url": "https://www.lvvwd.com/assets/pdf/water-quality-report-las-vegas-valley-current.pdf", "evidence_ids": [ "LASVEG-L-01" ] }, "source_water": { "text": "About 90 percent of Las Vegas Valley water comes from Lake Mead, and about 10 percent from wells in a deep valley aquifer.", "source_title": "Las Vegas Valley Water District 2026 Water Quality Report", "source_url": "https://www.lvvwd.com/assets/pdf/water-quality-report-las-vegas-valley-current.pdf", "evidence_ids": [ "LASVEG-L-02" ] }, "seasonal": { "text": "Groundwater is used mainly from April through October to meet peak demand, so some areas get a blend of well water and Lake Mead water then.", "source_title": "Las Vegas Valley Water District 2026 Water Quality Report", "source_url": "https://www.lvvwd.com/assets/pdf/water-quality-report-las-vegas-valley-current.pdf", "evidence_ids": [ "LASVEG-L-03" ] } }, "sources_checked_on": "2026-10-26", "site": "https://vegaswatersystems.com/", "brand": "Vegas Water Systems by My Home Water System", "taking_requests": true }, { "city": "New York City", "state": "NY", "slug": "new-york", "hardness_facts": [ { "utility": "NYC DEP", "measure": "Total hardness", "value_as_published": "Average 32 mg/L (2 grains per gallon), range 18-100 mg/L", "period": "Calendar year 2025", "source_title": "New York City Drinking Water Supply and Quality Report 2025", "source_url": "https://www.nyc.gov/assets/dep/downloads/pdf/water/drinking-water/drinking-water-supply-quality-report/2025-drinking-water-supply-quality-report.pdf" } ], "published_span_mg_per_l": [ 18, 100 ], "span_converted_from_grains": false, "usgs_class": "soft to moderately hard", "usgs_class_source": "https://www.usgs.gov/water-science-school/science/hardness-water", "notes": [], "local_details": { "disinfectant": { "text": "New York City disinfects with chlorine, and Croton water also gets ultraviolet light. The 2025 report does not mention chloramine.", "kind": "chlorine", "source_title": "NYC 2025 Drinking Water Supply and Quality Report", "source_url": "https://www.nyc.gov/assets/dep/downloads/pdf/water/drinking-water/drinking-water-supply-quality-report/2025-drinking-water-supply-quality-report.pdf", "evidence_ids": [ "NEWYOR-L-01" ] }, "source_water": { "text": "New York City water comes from upstate reservoirs: the Catskill and Delaware systems supplied 91.3 percent in 2025 and the Croton system 8.7 percent.", "source_title": "NYC 2025 Drinking Water Supply and Quality Report", "source_url": "https://www.nyc.gov/assets/dep/downloads/pdf/water/drinking-water/drinking-water-supply-quality-report/2025-drinking-water-supply-quality-report.pdf", "evidence_ids": [ "NEWYOR-L-02" ] } }, "sources_checked_on": "2026-10-27", "site": "https://nycwatersystems.com/", "brand": "NYC Water Systems by My Home Water System", "taking_requests": false }, { "city": "Cincinnati", "state": "OH", "slug": "cincinnati", "hardness_facts": [ { "utility": "Greater Cincinnati Water Works", "measure": "Average hardness, Miller Plant", "value_as_published": "Average 126 mg/L (7 grains per gallon)", "period": "Undated FAQ on the page for the 2025 report", "source_title": "Water Quality Reports (GCWW), Frequently Asked Questions: How hard is GCWW's water?", "source_url": "https://www.cincinnati-oh.gov/water/water-quality-and-treatment/water-quality-reports/" }, { "utility": "Greater Cincinnati Water Works", "measure": "Average hardness, Bolton Plant", "value_as_published": "Average 140 mg/L (8 grains per gallon)", "period": "Undated FAQ on the page for the 2025 report", "source_title": "Water Quality Reports (GCWW), Frequently Asked Questions: How hard is GCWW's water?", "source_url": "https://www.cincinnati-oh.gov/water/water-quality-and-treatment/water-quality-reports/" } ], "published_span_mg_per_l": [ 126, 140 ], "span_converted_from_grains": false, "usgs_class": "hard", "usgs_class_source": "https://www.usgs.gov/water-science-school/science/hardness-water", "notes": [ "Greater Cincinnati Water Works treats with ultraviolet light and chlorine.", "The utility does not say which plant serves which part of the city." ], "local_details": { "disinfectant": { "text": "Greater Cincinnati Water Works treats with ultraviolet light and chlorine.", "kind": "chlorine", "source_title": "Greater Cincinnati Water Works water quality reports page", "source_url": "https://www.cincinnati-oh.gov/water/water-quality-and-treatment/water-quality-reports/", "evidence_ids": [ "CINCIN-L-01" ] }, "source_water": { "text": "About 88 percent of Cincinnati water is Ohio River water from the Miller plant, and the rest is groundwater from the Great Miami Buried Valley Aquifer.", "source_title": "Greater Cincinnati Water Works water quality reports page", "source_url": "https://www.cincinnati-oh.gov/water/water-quality-and-treatment/water-quality-reports/", "evidence_ids": [ "CINCIN-L-02" ] } }, "sources_checked_on": "2026-10-27", "site": "https://cincinnatiwatersystems.com/", "brand": "Cincinnati Water Systems by My Home Water System", "taking_requests": false }, { "city": "Oklahoma City", "state": "OK", "slug": "oklahoma-city", "hardness_facts": [], "published_span_mg_per_l": null, "span_converted_from_grains": false, "usgs_class": null, "usgs_class_source": "https://www.usgs.gov/water-science-school/science/hardness-water", "notes": [ "OKC's water quality reports for 2016, 2017 and 2019 through 2025 list no hardness figure.", "A 2017 city plan describes Hefner water as generally hard and Draper water as much softer, and a 2024 city project document describes raw Lake Hefner water as high in hardness. Neither gives a number." ], "local_details": { "disinfectant": { "text": "OKC disinfects with a small amount of chlorine and ammonia, which forms chloramine, measured at 3.57 ppm at Hefner and 3.25 ppm at Draper in 2025.", "kind": "chloramine", "source_title": "OKC Utilities Consumer Confidence Report for 2025", "source_url": "https://www.okc.gov/files/assets/city/v/1/utilities/documents/water-quality-reports/ccr-june-2026-for-2025-reporting_063026cb-publishedv2071426.pdf", "evidence_ids": [ "OKLAHO-L-01" ] }, "source_water": { "text": "OKC draws on five reservoirs. Canton water flows down the North Canadian River to Lake Hefner, and Atoka and McGee Creek water travels by pipeline to Lake Stanley Draper, for treatment at the Hefner and Draper plants.", "source_title": "OKC Utilities Consumer Confidence Report for 2025", "source_url": "https://www.okc.gov/files/assets/city/v/1/utilities/documents/water-quality-reports/ccr-june-2026-for-2025-reporting_063026cb-publishedv2071426.pdf", "evidence_ids": [ "OKLAHO-L-02" ] }, "softening": { "text": "Partly. A 2024 city project document describes the Hefner plant as a lime softening plant. It does not describe the Draper plant.", "source_title": "OKC Hefner Water Treatment Plant Clarifier Rehabilitation (2024)", "source_url": "https://okc.gov/home/showpublisheddocument/42328/638525013580870000", "evidence_ids": [ "OKLAHO-L-03" ] }, "service": { "text": "OKC Utilities serves the city from its Hefner and Draper plants, except The Falls neighborhood, which gets City of Edmond water under an agreement.", "source_title": "OKC Utilities Consumer Confidence Report for 2025", "source_url": "https://www.okc.gov/files/assets/city/v/1/utilities/documents/water-quality-reports/ccr-june-2026-for-2025-reporting_063026cb-publishedv2071426.pdf", "evidence_ids": [ "OKLAHO-L-04" ] } }, "sources_checked_on": "2026-10-27", "site": "https://okcwatersystems.com/", "brand": "OKC Water Systems by My Home Water System", "taking_requests": false }, { "city": "Allentown", "state": "PA", "slug": "allentown", "hardness_facts": [ { "utility": "Lehigh County Authority", "measure": "Total hardness", "value_as_published": "Average 15.0 grains per gallon, range 10.5-16.6 grains per gallon", "period": "Calendar year 2025", "source_title": "Allentown Division, PWSID: 3390024, Annual Water Quality Report for 2025", "source_url": "https://lcawaterworks.org/wp-content/uploads/ALD.pdf" } ], "published_span_mg_per_l": [ 180, 284 ], "span_converted_from_grains": true, "usgs_class": "hard to very hard", "usgs_class_source": "https://www.usgs.gov/water-science-school/science/hardness-water", "notes": [ "An undated Lehigh County Authority web page gives 13 grains per gallon for the Allentown Division, lower than the average in its 2025 report." ], "local_details": { "disinfectant": { "text": "Lehigh County Authority uses chlorine as its main disinfectant in Allentown.", "kind": "chlorine", "source_title": "Lehigh County Authority, Allentown Division 2025 Water Quality Report", "source_url": "https://lcawaterworks.org/wp-content/uploads/ALD.pdf", "evidence_ids": [ "ALLENT-L-01" ] }, "source_water": { "text": "Allentown water comes from Crystal Spring and Schantz Spring plus the Little Lehigh Creek and the Lehigh River.", "source_title": "Lehigh County Authority, Allentown Division 2025 Water Quality Report", "source_url": "https://lcawaterworks.org/wp-content/uploads/ALD.pdf", "evidence_ids": [ "ALLENT-L-02" ] } }, "sources_checked_on": "2026-10-27", "site": "https://allentownwatersystems.com/", "brand": "Allentown Water Systems by My Home Water System", "taking_requests": false }, { "city": "Philadelphia", "state": "PA", "slug": "philadelphia", "hardness_facts": [ { "utility": "Philadelphia Water Department", "measure": "Hardness, Baxter plant", "value_as_published": "Average 101 ppm (6 grains per gallon), range 72-121 ppm", "period": "2025 report year", "source_title": "2025 Drinking Water Quality Report – Philadelphia Water Department (Hardness in Tap Water table)", "source_url": "https://water.phila.gov/2025-quality" }, { "utility": "Philadelphia Water Department", "measure": "Hardness, Belmont plant", "value_as_published": "Average 151 ppm (9 grains per gallon), range 99-204 ppm", "period": "2025 report year", "source_title": "2025 Drinking Water Quality Report – Philadelphia Water Department (Hardness in Tap Water table)", "source_url": "https://water.phila.gov/2025-quality" }, { "utility": "Philadelphia Water Department", "measure": "Hardness, Queen Lane plant", "value_as_published": "Average 169 ppm (10 grains per gallon), range 119-270 ppm", "period": "2025 report year", "source_title": "2025 Drinking Water Quality Report – Philadelphia Water Department (Hardness in Tap Water table)", "source_url": "https://water.phila.gov/2025-quality" } ], "published_span_mg_per_l": [ 72, 270 ], "span_converted_from_grains": false, "usgs_class": "moderately hard to very hard", "usgs_class_source": "https://www.usgs.gov/water-science-school/science/hardness-water", "notes": [ "Baxter draws from the Delaware River. Belmont and Queen Lane draw from the Schuylkill." ], "local_details": { "disinfectant": { "text": "Philadelphia Water Department disinfects with chloramine, a combination of chlorine and ammonia.", "kind": "chloramine", "source_title": "Philadelphia Water Department 2025 water quality report", "source_url": "https://water.phila.gov/2025-quality", "evidence_ids": [ "PHILAD-L-01" ] }, "source_water": { "text": "The Baxter plant draws from the Delaware River, and the Queen Lane and Belmont plants draw from the Schuylkill.", "source_title": "Philadelphia Water Department 2025 water quality report", "source_url": "https://water.phila.gov/2025-quality", "evidence_ids": [ "PHILAD-L-02" ] }, "by_area": { "text": "Hardness depends on which treatment plant serves your part of the city, and the department says seasonal changes can affect taste and odor.", "source_title": "Philadelphia Water Department 2025 water quality report", "source_url": "https://water.phila.gov/2025-quality", "evidence_ids": [ "PHILAD-L-03" ] } }, "sources_checked_on": "2026-10-27", "site": "https://philadelphiawatersystems.com/", "brand": "Philadelphia Water Systems by My Home Water System", "taking_requests": true }, { "city": "Pittsburgh", "state": "PA", "slug": "pittsburgh", "hardness_facts": [ { "utility": "Pittsburgh Water", "measure": "Hardness, as Pittsburgh Water describes it", "value_as_published": "\"Moderately hard\" (no number given)", "period": "Undated web page", "source_title": "Water Quality FAQ | Pittsburgh Water", "source_url": "https://www.pgh2o.com/node/5164" } ], "published_span_mg_per_l": null, "span_converted_from_grains": false, "usgs_class": null, "usgs_class_source": "https://www.usgs.gov/water-science-school/science/hardness-water", "notes": [ "Pittsburgh Water's 2019, 2020 and 2022 water quality reports list calcium but no hardness figure, and its 2021, 2024 and 2025 reports and its treatment FAQ are closed to automated reading, so we have no published number." ], "local_details": { "disinfectant": { "text": "Pittsburgh Water treats filtered water with chlorine.", "kind": "chlorine", "source_title": "Pittsburgh Water 2022 Water Quality Report", "source_url": "https://www.pgh2o.com/sites/default/files/2023-05/FINAL_PWSA_CCR_2022.pdf", "evidence_ids": [ "PITTSB-L-01" ] }, "source_water": { "text": "Pittsburgh Water draws all of its drinking water from the Allegheny River.", "source_title": "Pittsburgh Water, our water source", "source_url": "https://www.pgh2o.com/node/28", "evidence_ids": [ "PITTSB-L-02" ] }, "service": { "text": "Pittsburgh Water supplies most of the city. Some neighborhoods get only sewer service from it and buy water from another provider, such as Pennsylvania American Water, so check your bill.", "source_title": "Pittsburgh Water service area page", "source_url": "https://www.pgh2o.com/node/280", "evidence_ids": [ "PITTSB-L-03" ] } }, "sources_checked_on": "2026-10-27", "site": "https://pittsburghwatersystems.com/", "brand": "Pittsburgh Water Systems by My Home Water System", "taking_requests": false }, { "city": "Nashville", "state": "TN", "slug": "nashville", "hardness_facts": [ { "utility": "Metro Water Services", "measure": "Total hardness", "value_as_published": "100.5 mg/L, range 88.5-128.4 mg/L", "period": "2023 data, in the 2025 report", "source_title": "2025 Consumer Confidence Report", "source_url": "https://www.nashville.gov/sites/default/files/2026-05/2025_Consumer_Confidence_Report-FINAL.pdf?ct=1777986674" }, { "utility": "Metro Water Services", "measure": "Calcium hardness", "value_as_published": "75.3 mg/L, range 63.9-92.6 mg/L", "period": "Undated row, 2025 water quality report", "source_title": "2025 Water Quality Report (Nashville Metro Water Service PWSID TN0000494)", "source_url": "https://www.nashville.gov/sites/default/files/2026-04/Water_Quality_Report-2025.pdf?ct=1777578711" } ], "published_span_mg_per_l": [ 88.5, 128.4 ], "span_converted_from_grains": false, "usgs_class": "moderately hard to hard", "usgs_class_source": "https://www.usgs.gov/water-science-school/science/hardness-water", "notes": [ "Metro Water Services calls Nashville's water moderately hard. Calcium hardness is only part of total hardness." ], "local_details": { "disinfectant": { "text": "Metro Water Services disinfects with a small amount of bleach, a form of chlorine, averaging 1.60 ppm in its 2025 report.", "kind": "chlorine", "source_title": "Metro Water Services 2025 Consumer Confidence Report", "source_url": "https://www.nashville.gov/sites/default/files/2026-05/2025_Consumer_Confidence_Report-FINAL.pdf?ct=1777986674", "evidence_ids": [ "NASHVI-L-01" ] }, "source_water": { "text": "Metro Water draws from the Cumberland River and treats it at the K.R. Harrington and Omohundro plants.", "source_title": "Metro Water and Sewerage Services Annual Disclosure FY2025", "source_url": "https://www.nashville.gov/sites/default/files/2026-05/Metro_Water_and_Sewerage_Services_Annual_Disclosure_FY2025.pdf?ct=1778591132", "evidence_ids": [ "NASHVI-L-02" ] }, "service": { "text": "Metro Water serves most of Davidson County, but several separate utility districts, such as Harpeth Valley Utility District, also operate inside the county, so check your bill.", "source_title": "Metro Water and Sewerage Services Annual Disclosure FY2025", "source_url": "https://www.nashville.gov/sites/default/files/2026-05/Metro_Water_and_Sewerage_Services_Annual_Disclosure_FY2025.pdf?ct=1778591132", "evidence_ids": [ "NASHVI-L-03" ] } }, "sources_checked_on": "2026-10-27", "site": "https://nashvillewatersystems.com/", "brand": "Nashville Water Systems by My Home Water System", "taking_requests": false }, { "city": "Austin", "state": "TX", "slug": "austin", "hardness_facts": [ { "utility": "Austin Water", "measure": "Total hardness", "value_as_published": "Average 93 ppm (5.4 grains per gallon), range 70-126 ppm", "period": "Calendar year 2025", "source_title": "Water Quality Reports | Austin Water | AustinTexas.gov (2025 Consumer Confidence Report section)", "source_url": "https://www.austintexas.gov/water/programs/water-quality-reports" } ], "published_span_mg_per_l": [ 70, 126 ], "span_converted_from_grains": false, "usgs_class": "moderately hard to hard", "usgs_class_source": "https://www.usgs.gov/water-science-school/science/hardness-water", "notes": [], "local_details": { "disinfectant": { "text": "Austin Water lists chloramine as the disinfectant that controls microbes.", "kind": "chloramine", "source_title": "Austin Water 2025 Water Quality Report", "source_url": "https://www.austintexas.gov/water/programs/water-quality-reports", "evidence_ids": [ "AUSTIN-L-01" ] }, "source_water": { "text": "Austin Water draws from the Lower Colorado River as it flows through Lake Travis and Lake Austin.", "source_title": "Austin Water 2025 Water Quality Report", "source_url": "https://www.austintexas.gov/water/programs/water-quality-reports", "evidence_ids": [ "AUSTIN-L-02" ] }, "softening": { "text": "Yes. Austin Water uses lime softening, which it says also helps coat pipes against corrosion.", "source_title": "Austin Water 2025 Water Quality Report", "source_url": "https://www.austintexas.gov/water/programs/water-quality-reports", "evidence_ids": [ "AUSTIN-L-03" ] } }, "sources_checked_on": "2026-10-27", "site": "https://austinwatersystems.com/", "brand": "Austin Water Systems by My Home Water System", "taking_requests": false }, { "city": "Dallas", "state": "TX", "slug": "dallas", "hardness_facts": [ { "utility": "Dallas Water Utilities", "measure": "Total hardness", "value_as_published": "Average 119 mg/L, range 92-167 mg/L", "period": "Calendar year 2003", "source_title": "2003 Dallas Drinking Water Quality Report", "source_url": "https://dallascityhall.com/departments/waterutilities/DCH%20Documents/pdf/03engWQR.pdf" } ], "published_span_mg_per_l": [ 92, 167 ], "span_converted_from_grains": false, "usgs_class": "moderately hard to hard", "usgs_class_source": "https://www.usgs.gov/water-science-school/science/hardness-water", "notes": [ "The newest Dallas report we found that publishes hardness covers 2003. Later reports we checked, through 2025, have no hardness line." ], "local_details": { "disinfectant": { "text": "Dallas Water Utilities disinfects with chloramine instead of chlorine.", "kind": "chloramine", "source_title": "Dallas Water Utilities water quality information page", "source_url": "https://dallascityhall.com/departments/waterutilities/pages/water_quality_information.aspx", "evidence_ids": [ "DALLAS-L-01" ] }, "source_water": { "text": "Dallas uses surface water from the Elm Fork of the Trinity River and lakes Ray Roberts, Lewisville, Grapevine, Ray Hubbard, Tawakoni and Fork, treated at the East Side, Elm Fork and Bachman plants.", "source_title": "Dallas Water Quality Report", "source_url": "https://dallascityhall.com/departments/waterutilities/DCH%20Documents/pdf/water-quality-report.pdf", "evidence_ids": [ "DALLAS-L-02" ] } }, "sources_checked_on": "2026-10-27", "site": "https://dallaswatersystems.com/", "brand": "Dallas Water Systems by My Home Water System", "taking_requests": false }, { "city": "Fort Worth", "state": "TX", "slug": "fort-worth", "hardness_facts": [ { "utility": "Fort Worth Water", "measure": "Total hardness as CaCO3", "value_as_published": "76.5 to 175 ppm (5 to 10 grains per gallon), range only", "period": "Calendar year 2024", "source_title": "Fort Worth Water's 2024 water quality data for wholesale customers, as printed in Westworth Village's 2024 report", "source_url": "https://www.cityofwestworth.com/ArchiveCenter/ViewFile/Item/67" } ], "published_span_mg_per_l": [ 76.5, 175 ], "span_converted_from_grains": false, "usgs_class": "moderately hard to hard", "usgs_class_source": "https://www.usgs.gov/water-science-school/science/hardness-water", "notes": [ "Fort Worth's own 2023 and 2024 reports would not load for us. The 2024 figures above are Fort Worth Water's data as reprinted by Westworth Village, a city that buys Fort Worth water.", "Fort Worth's own 2022 report gave 100 to 171 ppm (6 to 10 grains per gallon)." ], "local_details": { "disinfectant": { "text": "Fort Worth Water lists chloramine as the additive that controls microbes, at 2.00 to 3.70 ppm in 2024.", "kind": "chloramine", "source_title": "Fort Worth Water's 2024 water quality data, printed in Westworth Village's 2024 report", "source_url": "https://www.cityofwestworth.com/ArchiveCenter/ViewFile/Item/67", "evidence_ids": [ "FORTWO-L-01" ] }, "source_water": { "text": "Fort Worth uses surface water from Lake Worth, Eagle Mountain Lake, Lake Bridgeport, Richland-Chambers Reservoir, Cedar Creek Reservoir, Lake Benbrook and the Clear Fork of the Trinity River.", "source_title": "Fort Worth Water's 2024 water quality data, printed in Westworth Village's 2024 report", "source_url": "https://www.cityofwestworth.com/ArchiveCenter/ViewFile/Item/67", "evidence_ids": [ "FORTWO-L-02" ] } }, "sources_checked_on": "2026-10-27", "site": "https://fortworthwatersystems.com/", "brand": "Fort Worth Water Systems by My Home Water System", "taking_requests": false }, { "city": "Houston", "state": "TX", "slug": "houston", "hardness_facts": [ { "utility": "Houston Public Works", "measure": "Total hardness, main system", "value_as_published": "Average 135.5 ppm, range 43.5-229 ppm", "period": "Calendar year 2025", "source_title": "Houston Water Quality Report | Jan - Dec 2025", "source_url": "https://www.houstonpublicworks.org/sites/g/files/nwywnm456/files/doc/003_2025_houston_water_quality_report.pdf" } ], "published_span_mg_per_l": [ 43.5, 229 ], "span_converted_from_grains": false, "usgs_class": "soft to very hard", "usgs_class_source": "https://www.usgs.gov/water-science-school/science/hardness-water", "notes": [ "Houston reports both chlorine and chloramine as disinfectants, without saying which system uses which.", "Several smaller Houston systems, such as Kingwood, report their own hardness in the same 2025 report." ], "local_details": { "disinfectant": { "text": "The main Houston system uses chloramine. Some smaller city systems served only by wells, such as Kingwood, use chlorine.", "kind": "varies", "source_title": "Houston 2025 Water Quality Report", "source_url": "https://www.houstonpublicworks.org/sites/g/files/nwywnm456/files/doc/003_2025_houston_water_quality_report.pdf", "evidence_ids": [ "HOUSTO-L-01" ] }, "source_water": { "text": "The main system draws mostly surface water from the Trinity River (Lake Livingston) and San Jacinto River (Lake Conroe and Lake Houston), plus deep wells in the Evangeline and Chicot aquifers.", "source_title": "Houston 2025 Water Quality Report", "source_url": "https://www.houstonpublicworks.org/sites/g/files/nwywnm456/files/doc/003_2025_houston_water_quality_report.pdf", "evidence_ids": [ "HOUSTO-L-02" ] }, "service": { "text": "Houston Public Works runs six separate water systems: the main system, Kingwood, Willow Chase, District 73, District 82 and Belleau Woods, which buys water from Humble. Each has its own results in the report.", "source_title": "Houston 2025 Water Quality Report", "source_url": "https://www.houstonpublicworks.org/sites/g/files/nwywnm456/files/doc/003_2025_houston_water_quality_report.pdf", "evidence_ids": [ "HOUSTO-L-03" ] } }, "sources_checked_on": "2026-10-27", "site": "https://houstonhomewatersystems.com/", "brand": "Houston Home Water Systems by My Home Water System", "taking_requests": true }, { "city": "McAllen", "state": "TX", "slug": "mcallen", "hardness_facts": [], "published_span_mg_per_l": null, "span_converted_from_grains": false, "usgs_class": null, "usgs_class_source": "https://www.usgs.gov/water-science-school/science/hardness-water", "notes": [ "McAllen's water quality reports for 2019 through 2025 list no hardness figure. The 2025 report says secondary measures like this are not required to be reported.", "The nearest published measure we found is U.S. Geological Survey river data for the Rio Grande below Falcon Dam (1996-2000), which lists calcium and magnesium but no hardness value, so we show no figure." ], "local_details": { "disinfectant": { "text": "McAllen treats incoming river water with chlorine dioxide, then adds chlorine and ammonia to form chloramine that carries through the pipes.", "kind": "chloramine", "source_title": "McAllen Public Utility 2025 Water Quality Report", "source_url": "https://www.mcallenpublicutility.com/assets/docs/quality-and-education/water-quality/water-quality-report-2025.pdf", "evidence_ids": [ "MCALLE-L-01" ] }, "source_water": { "text": "McAllen gets Rio Grande water released from Falcon and Amistad dams, moved by irrigation districts to the utility reservoirs and treated at its South and North plants.", "source_title": "McAllen Public Utility 2025 Water Quality Report", "source_url": "https://www.mcallenpublicutility.com/assets/docs/quality-and-education/water-quality/water-quality-report-2025.pdf", "evidence_ids": [ "MCALLE-L-02" ] } }, "sources_checked_on": "2026-10-27", "site": "https://mcallenwatersystems.com/", "brand": "McAllen Water Systems by My Home Water System", "taking_requests": false }, { "city": "New Braunfels", "state": "TX", "slug": "new-braunfels", "hardness_facts": [ { "utility": "New Braunfels Utilities", "measure": "Water hardness range", "value_as_published": "13.7 to 17.4 grains per gallon, described as \"very hard\"", "period": "Undated web page (the same range appears as 2017 data in NBU's 2018 report)", "source_title": "The Facts About Hard Water | New Braunfels Utilities", "source_url": "https://nbutexas.com/?p=1145" } ], "published_span_mg_per_l": [ 234, 298 ], "span_converted_from_grains": true, "usgs_class": "very hard", "usgs_class_source": "https://www.usgs.gov/water-science-school/science/hardness-water", "notes": [ "NBU's water quality reports for 2019 through 2025 do not list hardness, so the newest dated figure is from 2017. NBU's hard-water page still states the same range." ], "local_details": { "disinfectant": { "text": "NBU lists total chlorine as the additive that controls microbes, averaging 2.64 ppm in 2024.", "kind": "chlorine", "source_title": "New Braunfels Utilities 2024 Water Quality Report", "source_url": "https://www.nbutexas.com/wp-content/uploads/2025/06/2024-Water-Quality-Report-Brochure-8.5x11-FINAL.pdf", "evidence_ids": [ "NEWBRA-L-01" ] }, "source_water": { "text": "Most New Braunfels water is Guadalupe River water treated at the Gruene Road plant, supplemented by Edwards and Trinity aquifer wells and water bought as needed from Green Valley SUD and GBRA.", "source_title": "New Braunfels Utilities 2024 Water Quality Report", "source_url": "https://www.nbutexas.com/wp-content/uploads/2025/06/2024-Water-Quality-Report-Brochure-8.5x11-FINAL.pdf", "evidence_ids": [ "NEWBRA-L-02" ] }, "seasonal": { "text": "NBU says hardness can vary with location, water source and seasonal conditions.", "source_title": "New Braunfels Utilities water hardness page", "source_url": "https://nbutexas.com/?p=36730", "evidence_ids": [ "NEWBRA-L-03" ] } }, "sources_checked_on": "2026-10-27", "site": "https://newbraunfelswatersystems.com/", "brand": "New Braunfels Water Systems by My Home Water System", "taking_requests": true }, { "city": "San Antonio", "state": "TX", "slug": "san-antonio", "hardness_facts": [ { "utility": "San Antonio Water System", "measure": "Typical hardness", "value_as_published": "15 to 20 grains per gallon", "period": "Undated FAQ page", "source_title": "SAWS water quality FAQs", "source_url": "https://www.saws.org/your-water/water-quality/saws-water-quality-concerns/faqs/" } ], "published_span_mg_per_l": [ 257, 342 ], "span_converted_from_grains": true, "usgs_class": "very hard", "usgs_class_source": "https://www.usgs.gov/water-science-school/science/hardness-water", "notes": [ "SAWS water comes from the Edwards, Carrizo, Simsboro, Trinity and Wilcox aquifers, and some areas also get surface water from Canyon Lake.", "SAWS's 2026 annual report does not list hardness. It reports a free chlorine residual averaging 1.46 ppm in 2025." ], "local_details": { "disinfectant": { "text": "SAWS keeps a free chlorine residual, averaging 1.46 ppm in 2025.", "kind": "chlorine", "source_title": "SAWS 2026 Water Quality Report", "source_url": "https://www.saws.org/wp-content/uploads/2026/06/2026-SAWS-Water-Quality-Report.pdf", "evidence_ids": [ "SANANT-L-01" ] }, "source_water": { "text": "Most SAWS water is groundwater from the Edwards, Carrizo, Simsboro, Trinity and Wilcox aquifers, with Canyon Lake surface water in some areas.", "source_title": "SAWS 2026 Water Quality Report", "source_url": "https://www.saws.org/wp-content/uploads/2026/06/2026-SAWS-Water-Quality-Report.pdf", "evidence_ids": [ "SANANT-L-02" ] } }, "sources_checked_on": "2026-10-26", "site": "https://sanantoniohomewatersystems.com/", "brand": "San Antonio Home Water Systems by My Home Water System", "taking_requests": true }, { "city": "Seattle", "state": "WA", "slug": "seattle", "hardness_facts": [ { "utility": "Seattle Public Utilities", "measure": "Hardness, Cedar distribution sample", "value_as_published": "1.55 grains per gallon", "period": "Single sample, May 2026", "source_title": "SPU Quarterly Surface Water Analysis (May 2026), non-regulatory data", "source_url": "https://www.seattle.gov/documents/Departments/SPU/Services/Water/Analyses/SPU_Quarterly-Surface-Water-Analysis_05-20-2026.pdf" }, { "utility": "Seattle Public Utilities", "measure": "Hardness, Tolt distribution sample", "value_as_published": "1.53 grains per gallon", "period": "Single sample, May 2026", "source_title": "SPU Quarterly Surface Water Analysis (May 2026), non-regulatory data", "source_url": "https://www.seattle.gov/documents/Departments/SPU/Services/Water/Analyses/SPU_Quarterly-Surface-Water-Analysis_05-20-2026.pdf" } ], "published_span_mg_per_l": [ 26, 27 ], "span_converted_from_grains": true, "usgs_class": "soft", "usgs_class_source": "https://www.usgs.gov/water-science-school/science/hardness-water", "notes": [ "In 2025, 62 percent of the water came from the Cedar River and 38 percent from the Tolt.", "Seattle publishes these as informational single samples, not an annual average." ], "local_details": { "disinfectant": { "text": "Seattle Public Utilities lists free chlorine in both its Cedar and Tolt supplies. Its reports do not mention chloramine.", "kind": "chlorine", "source_title": "SPU quarterly surface water analysis, May 2026", "source_url": "https://www.seattle.gov/documents/Departments/SPU/Services/Water/Analyses/SPU_Quarterly-Surface-Water-Analysis_05-20-2026.pdf", "evidence_ids": [ "SEATTL-L-01" ] }, "source_water": { "text": "In 2025, 62 percent of Seattle water came from the Cedar River and 38 percent from the South Fork Tolt River.", "source_title": "SPU 2025 Drinking Water Quality Report", "source_url": "https://seattle.gov/documents/Departments/SPU/AboutUs/Reports/Water%20Quality/SPU-Drinking-Water-Quality-Report_2025.pdf", "evidence_ids": [ "SEATTL-L-02" ] }, "by_area": { "text": "Homes south of Green Lake usually get Cedar River water, and areas north of Green Lake usually get Tolt water, though either source can serve other areas.", "source_title": "SPU 2025 Drinking Water Quality Report", "source_url": "https://seattle.gov/documents/Departments/SPU/AboutUs/Reports/Water%20Quality/SPU-Drinking-Water-Quality-Report_2025.pdf", "evidence_ids": [ "SEATTL-L-03" ] } }, "sources_checked_on": "2026-10-27", "site": "https://seattlewatersystems.com/", "brand": "Seattle Water Systems by My Home Water System", "taking_requests": false }, { "city": "Madison", "state": "WI", "slug": "madison", "hardness_facts": [ { "utility": "Madison Water Utility", "measure": "Hardness, citywide", "value_as_published": "18-20 grains per gallon", "period": "Undated FAQ", "source_title": "Madison Water Utility: Water Quality Frequently Asked Questions", "source_url": "https://www.cityofmadison.com/water/water-quality/faq" }, { "utility": "Madison Water Utility", "measure": "Hardness, Unit Well 6", "value_as_published": "450 mg/L (26 grains per gallon)", "period": "Calendar year 2025", "source_title": "Unit Well #6 water quality report", "source_url": "https://www.cityofmadison.com/water/documents/water-quality/Well06QualityReport.pdf" }, { "utility": "Madison Water Utility", "measure": "Hardness, Unit Well 14", "value_as_published": "580 mg/L (34 grains per gallon)", "period": "Calendar year 2025", "source_title": "Unit Well #14 water quality report", "source_url": "https://www.cityofmadison.com/water/documents/water-quality/Well14QualityReport.pdf" } ], "published_span_mg_per_l": [ 308, 580 ], "span_converted_from_grains": true, "usgs_class": "very hard", "usgs_class_source": "https://www.usgs.gov/water-science-school/science/hardness-water", "notes": [ "Hardness differs from well to well. The 22 well reports we read give 270 to 580 mg/L, and nine of them are harder than the citywide FAQ figure." ], "local_details": { "disinfectant": { "text": "Madison Water Utility disinfects with chlorine and says it does not use chloramine.", "kind": "chlorine", "source_title": "Madison Water Utility water quality FAQ", "source_url": "https://www.cityofmadison.com/water/water-quality/faq", "evidence_ids": [ "MADISO-L-01" ] }, "source_water": { "text": "Madison water is all groundwater, pumped by 21 active wells from a deep sandstone aquifer under the city.", "source_title": "Madison Water Utility water quality report", "source_url": "https://www.cityofmadison.com/water/documents/water-quality/WaterQualityEnglish.pdf", "evidence_ids": [ "MADISO-L-02" ] }, "by_area": { "text": "Each Madison well serves its own part of town, and the utility publishes a separate quality report for each well, so water differs by neighborhood.", "source_title": "Madison Water Utility water quality report", "source_url": "https://www.cityofmadison.com/water/documents/water-quality/WaterQualityEnglish.pdf", "evidence_ids": [ "MADISO-L-03" ] } }, "sources_checked_on": "2026-10-27", "site": "https://madisonwatersystems.com/", "brand": "Madison Water Systems by My Home Water System", "taking_requests": false } ] }