EWG Investigation | U.S. Tap Water Quality Database

Health Limit Exceeded
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Legal Limit
• EPA set legal limit which balances health concerns and treatment costs

Tier 3 Control - past mining and drilling
• Closed or abandoned mines/plans/notices
• Mineral rich land that has been titled to mining interests (mining patents)
• Formerly drilled and pumped oil & gas Leases

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NATIONAL SUMMARY

Quality Varies Across the U.S.

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Tap Water Quality Report
The State of California
4,395 Water Systems
Serving 57,507,363 People

An Environmental Working Group analysis of tap water tests from 1998 through 2003 for 4,395 communities across California shows 145 pollutants were found in drinking water across the state.

Pollution Summary

145	Total Contaminants Detected (1998 - 2003)
35	Agricultural Pollutants (pesticides, fertilizer, factory farms) Ammonia, Chlorate, Nitrate & nitrite, Nitrate, Nitrite, Phosphate, Sulfate, Thallium (total), Dalapon, Diquat, Simazine, Picloram, Dinoseb, Aldicarb sulfone, Metolachlor, Atrazine, Heptachlor, Propachlor, Dacthal, Diuron, 2,4-D, 2,4,5-TP (Silvex), Dichlorprop, Bromomethane, Aldrin, 1,3-Dichloropropene, Dicamba, Chloropicrin, Metribuzin, Molinate (Ordram), Thiobencarb (Bolero), 1,2 Dibromo-3-chloropropane (DBCP), Ethylene dibromide (EDB), Ethylbenzene, Perchlorate
31	Sprawl and Urban Pollutants (road runoff, lawn pesticides, human waste) Ammonia, Arsenic (total), Cadmium (total), Copper, Hydrogen sulfide, Lead (total), Mercury (total inorganic), Nitrate & nitrite, Nitrate, Nitrite, Phosphate, Antimony (total), Lithium, Molybdenum, Trichlorofluoromethane, Acetone, Naphthalene, MTBE, Diethylphthalate, Di-n-butylphthalate, Butyl Benzylphthalate, Benzo[a]pyrene, Indeno[1,2,3-cd]pyrene, Chloropicrin, Trichlorotrifluoroethane, Xylenes (total), Tetrachloroethylene, Benzene, o-Xylene, n-Propylbenzene, Ethyl-t-butyl ether (ETBE)
100	Industrial Pollutants Aluminum, Ammonia, Bromide, Arsenic (total), Chlorate, Barium (total), Cadmium (total), Chromium (total), Cyanide, Hydrogen sulfide, Lead (total), Manganese, Mercury (total inorganic), Nitrate & nitrite, Nitrate, Nitrite, Phosphate, Selenium (total), Silver (total), Sulfate, Antimony (total), Beryllium (total), Chromium (hexavalent), Lithium, Molybdenum, Thallium (total), Vanadium, p-Isopropyltoluene, Di(2-Ethylhexyl) adipate, Di(2-ethylhexyl) phthalate, 1,4-Dioxane, Chloromethane, Dichlorodifluoromethane, Bromomethane, Chloroethane, Trichlorofluoromethane, n-Nitrosodiphenylamine, Acetone, Methyl ethyl ketone, Naphthalene, Methyl isobutyl ketone, MTBE, Acenaphthylene, Acenaphthene, Diethylphthalate, Di-n-butylphthalate, Butyl Benzylphthalate, Indeno[1,2,3-cd]pyrene, Pentachlorophenol, 1,2,4-Trichlorobenzene, cis-1,2-Dichloroethylene, Total polychlorinated biphenyls (PCBs), 1,1-Dichloropropene, 1,3-Dichloropropane, 1,2,3-Trichloropropane, 2,2-Dichloropropane, 1,2,4-Trimethylbenzene, 1,2,3-Trichlorobenzene, n-Butylbenzene, 1,3,5-Trimethylbenzene, Bromochloromethane, Chloropicrin, Glyoxal, Trichlorotrifluoroethane, Ethylene dibromide (EDB), Xylenes (total), Formaldehyde, Dichloromethane (methylene chloride), o-Chlorotoluene, p-Chlorotoluene, o-Dichlorobenzene, p-Dichlorobenzene, 1,1-Dichloroethylene, 1,1-Dichloroethane, trans-1,2-Dichloroethylene, 1,2-Dichloroethane, 1,1,1-Trichloroethane, Carbon tetrachloride, 1,2-Dichloropropane, Trichloroethylene, 1,1,2-Trichloroethane, 1,1,1,2-Tetrachloroethane, Tetrachloroethylene, Monochlorobenzene (Chlorobenzene), Benzene, Toluene, Ethylbenzene, Styrene, o-Xylene, n-Propylbenzene, m- & p- Xylene, Combined Radium (-226 & -228), Radium-226, Radium-228, Tritium, Alpha particle activity, Strontium-90, Perchlorate, Ethyl-t-butyl ether (ETBE), Gross beta particle activity (pCi/L)
30	Water Treatment and Distribution Byproducts (pipes and fixtures, treatment chemicals and byproducts) Chlorate, Chlorine dioxide, Chlorite, Bromate, Cadmium (total), Asbestos, Di(2-ethylhexyl) phthalate, Chloromethane, Methyl ethyl ketone, Benzo[a]pyrene, Dibromomethane, Bromochloromethane, Monochloroacetic acid, Dichloroacetic acid, Trichloroacetic acid, Monobromoacetic acid, Dibromoacetic acid, Bromochloroacetic acid, Total haloacetic acids, Chloropicrin, Glyoxal, Chloroform, Bromoform, Bromodichloromethane, Dibromochloromethane, Total trihalomethanes (TTHMs), Formaldehyde, Bromodichloroacetic acid, Chlorodibromoacetic acid, Tribromoacetic acid
26	Naturally Occurring (naturally present but increased for lands denuded by sprawl, agriculture, or industrial development) Aluminum, Ammonia, Bromide, Arsenic (total), Chromium (total), Copper, Hydrogen sulfide, Lead (total), Manganese, Mercury (total inorganic), Nitrate & nitrite, Nitrate, Nitrite, Phosphate, Selenium (total), Silver (total), Sulfate, Chromium (hexavalent), Lithium, Chloromethane, Radon, Combined Radium (-226 & -228), Radium-226, Radium-228, Alpha particle activity, Gross beta particle activity (pCi/L)
67	Unregulated Contaminants EPA has not established a maximum legal limit in tapwater for these contaminants Ammonia, Bromide, Chlorate, Hydrogen sulfide, Phosphate, Lithium, Molybdenum, Vanadium, p-Isopropyltoluene, Aldicarb sulfone, Metolachlor, 1,4-Dioxane, Propachlor, Dacthal, Diuron, Dichlorprop, Chloromethane, Dichlorodifluoromethane, Bromomethane, Chloroethane, Trichlorofluoromethane, n-Nitrosodiphenylamine, Acetone, Methyl ethyl ketone, Naphthalene, Methyl isobutyl ketone, MTBE, Acenaphthylene, Acenaphthene, Diethylphthalate, Di-n-butylphthalate, Butyl Benzylphthalate, Indeno[1,2,3-cd]pyrene, 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, Bromochloromethane, Dicamba, Bromochloroacetic acid, Chloropicrin, Glyoxal, Metribuzin, Molinate (Ordram), Thiobencarb (Bolero), Trichlorotrifluoroethane, Formaldehyde, o-Chlorotoluene, p-Chlorotoluene, 1,1-Dichloroethane, 1,1,1,2-Tetrachloroethane, n-Propylbenzene, Radon, Tritium, Strontium-90, Perchlorate, Bromodichloroacetic acid, Chlorodibromoacetic acid, Tribromoacetic acid, Ethyl-t-butyl ether (ETBE)

145 64
35 14
31 15
100 43
30 16
26 19
Total pollutants Agricultural pollutants Sprawl and Urban pollutants Industrial pollutants Water Treatment and Distribution Byproducts Naturally occurring pollutants
Number of pollutants detected (1998 - 2003) Over health based limits

NOTE: Health based limits included in this analysis include enforceable drinking water limits (called Maximum Contaminant Limits, or MCLs) as well as governmental, non-enforceable health guidelines, such as Maximum Contaminant Limit Goals (MCLGs), lifetime health advisory levels, one-day and ten-day advisory levels to protect children from non-cancer health endpoints, and other government-established health guidelines for tap water contaminants.

Health Summary

The federal government has set standards for 80 chemical pollutants in tap water, balancing health concerns and treatment costs.

Contaminants found in state tap water (1998-2003): 145

Total population exposed above health-based limits: 46,852,770

Communities served water with contaminants above health-based limits: 1,603

Health effects or target organs of contaminants found: Cardiovascular or Blood Toxicity, Cancer, Developmental Toxicity, Endocrine Toxicity, Immunotoxicity, Kidney Toxicity, Gastrointestinal or Liver Toxicity, Neurotoxicity, Reproductive Toxicity, Respiratory Toxicity, and Skin Sensitivity.

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Contaminants found above health based limits: 64

Rank Contaminant Name Population Exposed (of 57,507,363 Total) Number of Water Systems (of 4,395) Total
At Any Level Above Health Limits
See Note With Detected Above Health Limits
See Note
1 Sulfate 48,972,520 0 2024 0
Substance from natural deposits, industrial processes, and agriculture
2 Alpha particle activity 47,950,762 30,129 1851 43
From mining waste polluants and natural sources
3 Nitrate 44,551,847 9,323,929 1843 168
Chemical that enters water from fertilizer runoff, leaching septic tanks, and erosion of natural deposits
4 Arsenic (total) 41,379,839 41,378,511 1061 1060
Metal that enters water by erosion of natural deposits, runoff from glass and electronics processing
5 Barium (total) 37,712,627 41,631 866 5
Mineral from drilling and mining waste runoff; erosion of natrual deposits
6 Chromium (total) 17,415,339 135 808 1
Discharge from steel and pulp mills; erosion of natural deposits
7 Manganese 21,517,523 2,324,108 789 313
element from natural deposits as well as industrial use
8 Total trihalomethanes (TTHMs) 25,627,979 7,302,045 702 223
Measure of four disinfection by-products
9 Nitrate & nitrite 36,729,317 54,070 664 16
Chemical that enters water from fertilizer runoff, leaching septic tanks, and erosion of natural deposits
10 Aluminum 24,189,379 396,181 662 25
Metal from metal refineries and mining operations

View Full Table

Testing Summary

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 273

Contaminants tested due to federal law: 99

Contaminants tested in addition to those required by federal law: 174

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Violations Summary

According to EPA, in 2003 6% of America's public water systems reported one or more violations of a health-based drinking water standard, and 26% reported significant violations of either monitoring and reporting requirements or health-based standards.

Reported violations (1998 - 2003): 5,444

Number of CA systems with violations: 2,499 (56.9%)

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Information on violations is drawn directly from EPA's national violations database in the Agency's Safe Drinking Water Information System. Analyses by others have raised questions about the quality of the information in EPA's database. For the purposes of this investigation, EWG is not showing below or including in our analyses, those violations for individual water suppliers that occurred on days for which the total number of violations assigned by EPA to that water supplier was greater than 20. This criteria was based on common characteristics of incorrect violations data as identified by water utilities, from a review of EPA's violations data by several hundred utilities prior to the release of EWG's investigation.