The Power of Information

National Drinking Water Database


2,655 systems serving 54,146,711 people

This drinking water quality report shows results of tests conducted by water utilities in California, provided to the Environmental Working Group (EWG) by the California Department of Public Health. It is part of EWG's national database that includes 47,667 drinking water utilities and 20 million test results from 45 states and the District of Columbia. Water utilities nationwide detected more than 300 pollutants between 2004 and 2009. More than half of these chemicals are unregulated, legal in any amount. Despite this widespread contamination, the federal government invests few resources in protecting rivers, reservoirs, and groundwater from pollution in the first place. The information below summarizes drinking water quality for this state.

Water Utilities
Population Served
Detected Chemicals
Exceed health guidelines*
Exceed Legal Limits*
Unregulated chemicals detected
* Water utilities are noted as exceeding the legal limit if any test is above the maximum contaminant level (MCL). Most MCLs are based on annual averages so exceeding the MCL for one test does not necessarily indicate that the system is out of compliance.

81 Contaminants Exceeding Health Based Limits

Contaminants detected in California drinking water above health guidelines, according to an Environmental Working Group analysis of data obtained from state water authorities

Number of Systems
At Any Level Above Health Limits At Any Level Above Health Limits
Alpha particle activity43,647,43243,647,4321,9001,900
Arsenic (total)41,950,09441,950,0941,2371,237
Total trihalomethanes (TTHMs)46,123,08238,126,578936486
Total haloacetic acids (HAAs)34,007,09133,966,183422418

Water Utilities in California Reporting Chemicals Exceeding Health Guidelines

Water utilities in California reporting chemicals exceeding health guidelines, according to an Environmental Working Group analysis of data obtained from state water authorities, include:

Chemicals tested
Chemicals found
Chemicals exceeding
health guidelines
Cwsc Salinas98,7301764424
Pomona - City, Water Dept.156,5001964824
Redlands City Mud-Water Div69,3001673423
City of Corona150,2531683723
San Gabriel Valley Water Co.-El Monte153,6572294823
City of Modesto190,1061763721
Crescenta Valley Cwd31,0001433721
Cws - Bakersfield193,9141864221
West Valley Water District44,7681603220
Suburban Water Systems-San Jose110,6021083220
City of Bakersfield105,6001783819
City of Fresno Water Division390,3501453419
City of Daly City92,3112183918
San Gabriel Valley WC - Fontana102,5991854318
California Water Service Co-Leona Valley1,4451683018
Glendale-City, Water Dept.200,0001984218
Valley County Water Dist.55,0001383818
California Water Service-S San Francisco54,0601573517
California Water Service - Stockton155,6701563417
Camp Pendleton (South)39,9152143217

Sources of California Drinking Water Contaminants

The contaminants identified in California drinking water come from a wide variety of sources, including agriculture, industry, water treatment plants, and polluted storm runoff from urban areas.

182Total Contaminants Detected (2004 - 2009)
54Agricultural Pollutants
(pesticides, fertilizer, factory farms)

Nitrate, Nitrate & nitrite, Arsenic (total), Selenium (total), Nitrite, Perchlorate, 1,2-Dibromo-3-chloropropane (DBCP), Atrazine, Ethylbenzene, Dalapon, Cyanide, n-Nitrosodimethylamine, Foaming agents (surfactants), Simazine, Chlorate, Ethylene dibromide (EDB), 1,2-Dichloropropane, Dacthal, Metolachlor, p-Dichlorobenzene, 2,4-D, Bromomethane, Monochlorobenzene (Chlorobenzene), o-Dichlorobenzene, Alachlor (Lasso), Lindane, Picloram, Dieldrin, Dinoseb, Dicamba, Diquat, Methoxychlor, Endrin, Aldicarb sulfoxide, Diuron, Methomyl, 1,3-Dichloropropene, Metribuzin, Glyphosate, Bromacil, Aldrin, Endothall, Butachlor, 2,4,5-T, Bentazon (Basagran), Tebuthiuron, Trifluralin, Di-n-octylphthalate, Thiobencarb (Bolero), Molinate (Ordram), Diazinon (Spectracide), Prometryn, Merphos, n-Nitroso di-N-Propylamine

57Sprawl and Urban Pollutants
(road runoff, lawn pesticides, human waste)

Nitrate, Copper, Nitrate & nitrite, Lead (total), Arsenic (total), Tetrachloroethylene, MTBE, Nitrite, Xylenes (total), Dalapon, Cadmium (total), Antimony (total), Mercury (total inorganic), m- & p- Xylene, Dichloromethane (methylene chloride), Cyanide, o-Xylene, Foaming agents (surfactants), Benzene, Acetone, Molybdenum, Silver (total), Trichlorofluoromethane, Dacthal, p-Dichlorobenzene, Methyl ethyl ketone, Di(2-Ethylhexyl) adipate, Lithium, Hydrogen sulfide, Di-n-butylphthalate, 2,4-D, Naphthalene, Benzo[a]pyrene, Trichlorotrifluoroethane, Lindane, Diethylphthalate, n-Propylbenzene, Phenanthrene, Pyrene, Butyl Benzylphthalate, Fluoranthene, Glyphosate, sec-Butylbenzene, Chrysene, Benzo[b]fluoranthene, 2,4,5-T, Anthracene, Benzo[k]fluoranthene, Benzo[a]anthracene, 2,3,7,8-TCDD (Dioxin), Dimethylphthalate, Trifluralin, Di-n-octylphthalate, Ethyl-t-butyl ether (ETBE), Diazinon (Spectracide), Caffeine, Ethylene Glycol

126Industrial Pollutants

Nitrate, Nitrate & nitrite, Barium (total), Lead (total), Arsenic (total), Manganese, Radium-228, Radium-226, Alpha particle activity, Alpha particle activity (excl radon and uranium), Combined Radium (-226 & -228), Gross beta particle activity (pCi/L), Combined Uranium (pCi/L), Tetrachloroethylene, Trichloroethylene, Chromium (total), Combined Uranium (mg/L), Aluminum, Selenium (total), MTBE, Nitrite, Perchlorate, Xylenes (total), cis-1,2-Dichloroethylene, Chlorite, 1,1-Dichloroethylene, Vanadium, Di(2-ethylhexyl) phthalate, Bromide, 1,2,3-Trichloropropane, Carbon tetrachloride, Ethylbenzene, Toluene, 1,1,1-Trichloroethane, Cadmium (total), Chromium (hexavalent), Dichlorodifluoromethane, Antimony (total), Mercury (total inorganic), 1,1-Dichloroethane, m- & p- Xylene, Chloromethane, Dichloromethane (methylene chloride), Cyanide, o-Xylene, Beryllium (total), Thallium (total), 1,2-Dichloroethane, n-Nitrosodimethylamine, Foaming agents (surfactants), Chlorine dioxide, Benzene, Acetone, Molybdenum, Chlorate, Ethylene dibromide (EDB), 1,2-Dichloropropane, Silver (total), Tritium, Trichlorofluoromethane, Vinyl chloride, 1,4-Dioxane, p-Dichlorobenzene, Methyl ethyl ketone, Di(2-Ethylhexyl) adipate, trans-1,2-Dichloroethylene, Strontium-90, Asbestos, Hexachlorocyclopentadiene, Lithium, Hydrogen sulfide, Styrene, Di-n-butylphthalate, Naphthalene, Monochlorobenzene (Chlorobenzene), 1,2,4-Trimethylbenzene, Methyl isobutyl ketone, Pentachlorophenol, Dibromomethane, Bromochloromethane, 1,1,2-Trichloroethane, Trichlorotrifluoroethane, Chloroethane, Lindane, Diethylphthalate, 1,2,4-Trichlorobenzene, Isopropylbenzene, 1,3,5-Trimethylbenzene, n-Propylbenzene, Phenanthrene, Tert-Butyl Alcohol, 1,2,3-Trichlorobenzene, Hexachlorobenzene (HCB), Pyrene, o-Chlorotoluene, p-Isopropyltoluene, n-Butylbenzene, Acetaldhyde, Butyl Benzylphthalate, Fluoranthene, Hexachlorobutadiene, Isophorone, Formaldehyde, sec-Butylbenzene, 2,2-Dichloropropane, Total polychlorinated biphenyls (PCBs), p-Chlorotoluene, Chrysene, Benzo[b]fluoranthene, cis-1,3-Dichloropropene, 1,3-Dichloropropane, 1,1-Dichloropropene, Anthracene, Glyoxal, Acenaphthylene, 2,3,7,8-TCDD (Dioxin), Dimethylphthalate, Di-n-octylphthalate, Nitrobenzene, N-nitrosopyrrolidine (npyr), Tert-Amyl-Methyl Ether, Ethyl-t-butyl ether (ETBE), Isopropyl ether, N-nitrosodi-n-butylamine (ndba), n-Nitroso di-N-Propylamine, Ethylene Glycol

32Water Treatment and Distribution Byproducts
(pipes and fixtures, treatment chemicals and byproducts)

Total trihalomethanes (TTHMs), Total haloacetic acids (HAAs), Chloroform, Bromodichloromethane, Dibromochloromethane, Dichloroacetic acid, Trichloroacetic acid, Bromoform, Dibromoacetic acid, Monochloroacetic acid, Bromochloroacetic acid, Monobromoacetic acid, Chlorite, Di(2-ethylhexyl) phthalate, Bromodichloroacetic acid, Cadmium (total), Chloromethane, n-Nitrosodimethylamine, Chlorine dioxide, Chlorate, Bromate, Vinyl chloride, Asbestos, Dibromomethane, Bromochloromethane, Benzo[a]pyrene, Chloroethane, Fluoranthene, Formaldehyde, Benzo[k]fluoranthene, Glyoxal, Benzo[a]anthracene

28Naturally Occurring
(naturally present but increased for lands denuded by sprawl, agriculture, or industrial development)

Nitrate, Copper, Nitrate & nitrite, Barium (total), Lead (total), Arsenic (total), Manganese, Radium-228, Radium-226, Alpha particle activity, Alpha particle activity (excl radon and uranium), Combined Radium (-226 & -228), Gross beta particle activity (pCi/L), Combined Uranium (pCi/L), Chromium (total), Combined Uranium (mg/L), Aluminum, Selenium (total), Nitrite, Radon, Bromide, Chromium (hexavalent), Mercury (total inorganic), Chloromethane, Cyanide, Silver (total), Lithium, Hydrogen sulfide

95Unregulated Contaminants
EPA has not established a maximum legal limit in tapwater for these contaminants

Bromide, Chlorate, Chlorine dioxide, Hydrogen sulfide, Lead (total), Lithium, Molybdenum, Vanadium, Methomyl, p-Isopropyltoluene, Aldicarb sulfoxide, Metolachlor, 1,4-Dioxane, Trifluralin, Diazinon (Spectracide), Dieldrin, Butachlor, Bromacil, Dacthal, Diuron, 2,4,5-T, Chloromethane, Dichlorodifluoromethane, Bromomethane, Chloroethane, Trichlorofluoromethane, Di-n-octylphthalate, cis-1,3-Dichloropropene, Acetone, Isopropyl ether, Hexachlorobutadiene, Methyl ethyl ketone, Naphthalene, Methyl isobutyl ketone, MTBE, Nitrobenzene, Acenaphthylene, Isophorone, Tebuthiuron, Phenanthrene, Anthracene, Dimethylphthalate, Diethylphthalate, Fluoranthene, Pyrene, Di-n-butylphthalate, Butyl Benzylphthalate, Chrysene, Benzo[a]anthracene, Benzo[b]fluoranthene, Benzo[k]fluoranthene, n-Nitrosodimethylamine, n-Nitroso di-N-Propylamine, Aldrin, Dibromomethane, 1,1-Dichloropropene, 1,3-Dichloropropane, 1,3-Dichloropropene, 1,2,3-Trichloropropane, 2,2-Dichloropropane, 1,2,4-Trimethylbenzene, 1,2,3-Trichlorobenzene, n-Butylbenzene, 1,3,5-Trimethylbenzene, sec-Butylbenzene, Bromochloromethane, Dicamba, Bromochloroacetic acid, Acetaldhyde, Glyoxal, Metribuzin, Bentazon (Basagran), Molinate (Ordram), Thiobencarb (Bolero), Trichlorotrifluoroethane, Ethylene Glycol, Formaldehyde, o-Chlorotoluene, p-Chlorotoluene, 1,1-Dichloroethane, Isopropylbenzene, n-Propylbenzene, Radon, Tritium, Strontium-90, Perchlorate, Bromodichloroacetic acid, Ethyl-t-butyl ether (ETBE), Merphos, Prometryn, Tert-Butyl Alcohol, Tert-Amyl-Methyl Ether, N-nitrosopyrrolidine (npyr), N-nitrosodi-n-butylamine (ndba), Caffeine

Testing Summary for California

The federal government has set standards for some of the pollutants found in tap water supplies.

Contaminants reported as tested by water suppliers in California389
 Contaminants tested due to federal law: 100
 Contaminants tested in addition to those required by federal law: 289

Violation Summary for California

Data from the U.S. Environmental Protection Agency includes the following violations of federal standards in California since 2004

Violation TypeNumber of Violations
Failure to monitor, Routine Major (Coliform bacteria)1,061
Maximum contaminant level, Monthly (Coliform bacteria)1,021
Failure to monitor regularly859
Over maximum contaminant level, Average809
Monitoring and Reporting Disinfection Byproduct Rule410
Failure to report information to the public or state agency in the Consumer Confidence Report333
Failure to monitor, Routine Minor (Coliform bacteria)218
Over maximum contaminant level, Single Sample178
Failure to monitor, Repeat Major (Coliform bacteria)127
Failure to monitor, Repeat Minor (Coliform bacteria)125
Treatment Technique (Surface Water Treatment Rule)88
Follow-up and Routine Tap Sampling73
Maximum contaminant level, Acute (Coliform bacteria)66
Failure to monitor: Check/Repeat/Confirmation sampling25
Failure to monitor or report, Routine/Repeat (Indicators of microbial or virus contamination)23
Excess Turbidity at 0.3 NTU21
Initial Tap Sampling for Lead and Copper18
Failure to notify state agency11
Operations Report10
Variance/Exemption/Other Compliance8
Failure to notify public of violation6
Treatment Technique No Certif. Operator6
Optimal Corrosion Control Treatment Installation/Demonstration5
Inadequate reporting of information to the public5
Failure to monitor or report, Routine/Repeat (Indicators of microbial or virus contamination)3
Excess Turbidity at 1 NTU2
Public Education1
Failure to Filter (Surface Water Treatment Rule)1
Initial, Follow-up, or Routine Source Water Treatment Monitoring and Reporting1