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 activity 43,647,432 43,647,432 1,900 1,900
Arsenic (total) 41,950,094 41,950,094 1,237 1,237
Bromodichloromethane 41,004,984 41,004,984 642 642
Total trihalomethanes (TTHMs) 46,123,082 38,126,578 936 486
Dibromochloromethane 39,466,395 37,579,251 603 557
Radium-228 37,456,970 37,456,970 1,367 1,367
Bromoform 36,309,656 36,309,656 565 565
Chloroform 43,130,356 36,048,313 758 402
Total haloacetic acids (HAAs) 34,007,091 33,966,183 422 418
Radium-226 32,437,688 32,437,688 441 441

  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.

182 Total Contaminants Detected (2004 - 2009)
54 Agricultural 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

57 Sprawl 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

126 Industrial 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

32 Water 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

28 Naturally 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

95 Unregulated 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 California 389
  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 Type Number of Violations
Failure to monitor, Routine Major (Coliform bacteria) 1,061
Maximum contaminant level, Monthly (Coliform bacteria) 1,021
Failure to monitor regularly 859
Over maximum contaminant level, Average 809
Monitoring and Reporting Disinfection Byproduct Rule 410
Failure to report information to the public or state agency in the Consumer Confidence Report 333
Failure to monitor, Routine Minor (Coliform bacteria) 218
Over maximum contaminant level, Single Sample 178
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 Sampling 73
Maximum contaminant level, Acute (Coliform bacteria) 66
Failure to monitor: Check/Repeat/Confirmation sampling 25
Failure to monitor or report, Routine/Repeat (Indicators of microbial or virus contamination) 23
Excess Turbidity at 0.3 NTU 21
Initial Tap Sampling for Lead and Copper 18
Failure to notify state agency 11
Operations Report 10
Variance/Exemption/Other Compliance 8
Failure to notify public of violation 6
Treatment Technique No Certif. Operator 6
Inadequate reporting of information to the public 5
Optimal Corrosion Control Treatment Installation/Demonstration 5
Failure to monitor or report, Routine/Repeat (Indicators of microbial or virus contamination) 3
Excess Turbidity at 1 NTU 2
Failure to Filter (Surface Water Treatment Rule) 1
Initial, Follow-up, or Routine Source Water Treatment Monitoring and Reporting 1
Public Education 1

Sources : EWG (Environmental Working Group)