Your local water, explained
California water quality reports
Choose your county
Each county guide shows the named utility, source reports and home filtration guidance. Results are not presented as a county-wide average.
No matching reports. Try a county, city or water provider.
Los Angeles County
The detailed results below belong to LADWP. Its source averages span moderately hard to very hard water, so the supplying source matters when planning scale control.
Browse reports → CaliforniaSan Diego County
The detailed results below belong to the City of San Diego system. Its three City plant averages are very hard, while purchased treated water differs. Neighboring districts need their own data.
Browse reports → CaliforniaOrange County, California
The detailed results below belong to Anaheim Public Utilities. All three of its source hardness averages are very hard. Use the supplier on your bill to decide whether this report applies.
Browse reports → CaliforniaRiverside County
The detailed results below belong to Riverside Public Utilities. Its reported hardness average is very hard, but this groundwater blend does not represent every supplier across the county.
Browse reports → CaliforniaSan Bernardino County
The detailed results below belong to San Bernardino Municipal Water Department. Its very hard average supports scale treatment for that system; other districts and private wells need their own evidence.
Browse reports → CaliforniaSanta Clara County
San Jose Water’s 2025 report shows source hardness averages from 99 to 288 mg/L: moderately hard to very hard. This county guide starts with that utility’s main system and links to other local suppliers; it does not assign one result to all of Santa Clara County.
Browse reports → CaliforniaAlameda County
EBMUD’s 2025 hardness ranges span 14–160 mg/L across treatment plants, from soft to hard. This guide covers its Alameda County service area and points to other utility reports; Alameda County Water District and other suppliers must be checked separately.
Browse reports → CaliforniaSacramento County
The City of Sacramento’s 2025 report lists an 83 mg/L system hardness average, using 2023–2025 measurements. That is moderately hard. Sacramento County Water Agency and other county suppliers are separate systems; the city’s numbers are not a countywide water test.
Browse reports → CaliforniaContra Costa County
CCWD reports a 74 mg/L hardness average at both treatment plants; EBMUD reports plant ranges spanning 14–160 mg/L. Select the provider on your bill to see the relevant results. These are separate utility reports, not a blended Contra Costa County average.
Browse reports → CaliforniaFresno County
The City of Fresno’s 2025 report shows an average hardness of 129 mg/L, in the hard category. For homes on that supply, filtration plus softening is a sensible starting recommendation for chlorine and scale goals. Other county utilities and private wells need their own data.
Browse reports → CaliforniaKern County
This Kern County hub covers two Bakersfield water systems with separate 2025 reports. Compare the named provider results below, then open the Bakersfield city guide. These figures do not represent every county utility or private well.
Browse reports → CaliforniaVentura County
Review City of Oxnard Water results, water hardness, source dates, and home filtration guidance.
Browse reports → CaliforniaSan Francisco County
San Francisco is a consolidated city and county, but a county label still does not identify every water system. Start with SFPUC’s San Francisco retail report, then use the city guide for its hardness and treatment context.
Browse reports → CaliforniaSan Joaquin County
Review Cal Water — Stockton System results, water hardness, source dates, and home filtration guidance.
Browse reports → CaliforniaSan Mateo County
Review Cal Water — San Mateo System results, water hardness, source dates, and home filtration guidance.
Browse reports → CaliforniaStanislaus County
Review City of Modesto — Modesto System results, water hardness, source dates, and home filtration guidance.
Browse reports → CaliforniaSonoma County
Review City of Santa Rosa Water results, water hardness, source dates, and home filtration guidance.
Browse reports → CaliforniaTulare County
Review Cal Water — Visalia System results, water hardness, source dates, and home filtration guidance.
Browse reports → CaliforniaSolano County
Review City of Vallejo — Vallejo Service Area results, water hardness, source dates, and home filtration guidance.
Browse reports → CaliforniaPlacer County
Review City of Roseville Water results, water hardness, source dates, and home filtration guidance.
Browse reports → CaliforniaSanta Barbara County
Review City of Santa Barbara Water results, water hardness, source dates, and home filtration guidance.
Browse reports → CaliforniaMonterey County
Review Cal Water — Salinas System results, water hardness, source dates, and home filtration guidance.
Browse reports →Choose your city
Los Angeles
Hardness changes with your water supply. Chloramine is a separate filtration consideration.
Browse reports → CitySan Diego
Very hard City plant water makes scale control worth planning alongside chloramine filtration.
Browse reports → CityAnaheim
Very hard source averages, chlorine disinfection and a byproduct result close to its limit.
Browse reports → CityRiverside
A very hard groundwater blend: filtration and softening address different goals.
Browse reports → CitySan Bernardino
Very hard water, chlorine treatment and results that need their original dates.
Browse reports → CitySan Jose
San Jose Water customers: see what the source blend means for your home.
Browse reports → CityOakland
Start with EBMUD’s report, then confirm the water blend reaching your Oakland home.
Browse reports → CitySacramento
Moderately hard on average, with different figures for river water and groundwater.
Browse reports → CityConcord
CCWD customers in Concord: understand the report and your next step.
Browse reports → CityFresno
Hard-water average: a filter and softener can address different household goals.
Browse reports → CitySan Francisco
Moderately hard on average. Start with chloramine filtration goals.
Browse reports → CityLong Beach
Same city. Two supply zones with very different hardness.
Browse reports → CityBakersfield
Choose your water system before choosing your treatment.
Browse reports →County guides now include Ventura, San Joaquin, San Mateo, Stanislaus, Sonoma, Tulare, Solano, Placer, Santa Barbara and Monterey. Match the provider and system on your bill; separate supplies retain separate results.
What this means for your home
These are utility measurements, not a test at your tap or a current service advisory.
We keep each utility’s results separate, show the reported sample year, and distinguish averages, maxima and tap-sampling percentiles. Hardness classifications use USGS ranges. Missing data stays unknown.
Your water → your home → your system
Turn your report into a plan for your home.
Choose the system size, keep useful existing equipment, and review your filtration goals.