The Power of Information

National Drinking Water Database


City of Napa - Napa, CA


Serves 70,000 people - Test data available: 2004-2009

This drinking water quality report shows results of tests conducted by the water utility and 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. 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 to protecting rivers, reservoirs, and groundwater from pollution in the first place. The information below summarizes test results for this utility and lists potential health concerns.

 
This Drinking Water System
National Average
Exceed Health GuidelinesTests showing chemicals at concentrations above health guidelines established by federal and state health agencies. These guidelines are typically set at a levels that pose no significant health risk.
16 chemicals
4
Health Standard ExceedencesChemicals detected at concentrations above the legal limit, the Maximum Contaminant Level (MCLs) established by the U.S. EPA. 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.
2 chemicals
0.5
Pollutants FoundThe total number of contaminants detected since 2004, according to data provided by the state water agency.
32 chemicals
8
Tests ConductedThe total number of number of water quality tests conducted by water utilities and recorded in data provided by the state water agency.
7,122 tests
420

Contaminants Exceeding Health Guidelines

ContaminantAverage/
Maximum
Result
Health Limit
Exceeded
Legal Limit
Exceeded

Testing History

-Tested      -Detected      -Over Health Guidelines      -Over Legal Limit*
Total trihalomethanes (TTHMs)Total trihalomethanes constitute the sum of four disinfection byproducts: chloroform, bromodichloromethane, dibromochloromethane, and bromoform.50.5 ppb
107.25 ppb
Yes
9.8 ppb
Yes
80 ppb
Di(2-ethylhexyl) phthalateDi(2-ethylhexyl) phthalate is a pollutant from rubber and industrial chemical factories and a leachate from PVC pipes; it is classified by EPA as a probable human carcinogen.1.83 ppb
11 ppb
Yes
MCLGA non-enforceable health goal that is set at a level at which no known or anticipated adverse effect on the health of persons occurs and which allows an adequate margin of safety. Source: U.S. Environmental Protection Agency.: 0 ppb
Yes
6 ppb
BromodichloromethaneBromodichloromethane is a disinfection byproduct from the trihalomethane (THM) family, and is formed when chlorine, chloramines or other disinfectants react with organic and inorganic matter in water.12.01 ppb
25.25 ppb
Yes
MCLGA non-enforceable health goal that is set at a level at which no known or anticipated adverse effect on the health of persons occurs and which allows an adequate margin of safety. Source: U.S. Environmental Protection Agency.: 0 ppb
No
80 ppb
DibromochloromethaneDibromochloromethane is a disinfection byproduct from the trihalomethane (THM) family, and is formed when chlorine, chloramines or other disinfectants react with organic and inorganic matter in water.3.12 ppb
13.58 ppb
Yes
0.4 ppb
No
80 ppb
ChloroformChloroform is a disinfection byproduct from the trihalomethane (THM) family, and is formed when chlorine, chloramines or other disinfectants react with organic and inorganic matter in water.35.59 ppb
76.75 ppb
Yes
5.7 ppb
No
80 ppb
Dichloroacetic acidDichloroacetic acid is a disinfection byproduct regulated by EPA as one of five haloacetic acids that are formed when chlorine, chloramines or other disinfectants react with organic and inorganic matter in water.8.31 ppb
23.3 ppb
Yes
MCLGA non-enforceable health goal that is set at a level at which no known or anticipated adverse effect on the health of persons occurs and which allows an adequate margin of safety. Source: U.S. Environmental Protection Agency.: 0 ppb
No
60 ppb
Total haloacetic acids (HAAs)Total haloacetic acids refers to the sum of the concentrations of five related disinfection byproducts in a water sample: dichloroacetic acid, trichloroacetic acid, monochloroacetic acid, monobromoacetic acid and dibromoacetic acid.21.76 ppb
53.8 ppb
Yes
0.7 ppb
No
60 ppb
Trichloroacetic acidTrichloroacetic acid is a disinfection byproduct regulated by EPA as one of five haloacetic acids that are formed when chlorine, chloramines or other disinfectants react with organic and inorganic matter in water.13.11 ppb
29.43 ppb
Yes
20 ppb
No
60 ppb
BromoformBromoform is a disinfection byproduct from the trihalomethane (THM) family, and is formed when chlorine, chloramines or other disinfectants react with organic and inorganic matter in water.0.02 ppb
0.65 ppb
Yes
MCLGA non-enforceable health goal that is set at a level at which no known or anticipated adverse effect on the health of persons occurs and which allows an adequate margin of safety. Source: U.S. Environmental Protection Agency.: 0 ppb
No
80 ppb
Ethylene dibromide (EDB)Ethylene dibromide is a a pollutant from petroleum refineries that was formerly used as gasoline additive and a pesticide suspended from use by EPA in 1984.<0.01 ppb
0.02 ppb
Yes
MCLGA non-enforceable health goal that is set at a level at which no known or anticipated adverse effect on the health of persons occurs and which allows an adequate margin of safety. Source: U.S. Environmental Protection Agency.: 0 ppb
No
0.05 ppb
Cadmium (total)Cadmium is a metal used in the steel and plastic industries; it is released from corrosion of galvanized pipes, runoff from metal refineries, waste batteries and paints; contamination from fertilizers; and erosion of natural deposits.0.09 ppb
0.7 ppb
Yes
0.04 ppb
No
5 ppb
1,2-Dibromo-3-chloropropane (DBCP)1,2-Dibromo-3-chloropropane is a persistent pesticide and groundwater contaminant associated with male sterility and severe reproductive toxicity; historically used as a soil fumigant on bananas and pineapples; banned by EPA in early 1980s.0.02 ppb
0.17 ppb
Yes
MCLGA non-enforceable health goal that is set at a level at which no known or anticipated adverse effect on the health of persons occurs and which allows an adequate margin of safety. Source: U.S. Environmental Protection Agency.: 0 ppb
No
0.2 ppb
Lead (total)Lead is a metal that enters water by corrosion of household plumbing systems, discharge of industrial pollution and erosion of natural deposits.0.46 ppb
3.65 ppb
Yes
MCLGA non-enforceable health goal that is set at a level at which no known or anticipated adverse effect on the health of persons occurs and which allows an adequate margin of safety. Source: U.S. Environmental Protection Agency.: 0 ppb
No
Alpha particle activityAlpha particles are a form of radiation released from mining waste pollutants and natural sources.0.33 pCi/L
1.99 pCi/L
Yes
MCLGA non-enforceable health goal that is set at a level at which no known or anticipated adverse effect on the health of persons occurs and which allows an adequate margin of safety. Source: U.S. Environmental Protection Agency.: 0 pCi/L
No
15 pCi/L
Radium-228Radium-228 is a radioactive element usually found around uranium deposits.0.06 pCi/L
0.17 pCi/L
Yes
MCLGA non-enforceable health goal that is set at a level at which no known or anticipated adverse effect on the health of persons occurs and which allows an adequate margin of safety. Source: U.S. Environmental Protection Agency.: 0 pCi/L
No
5 pCi/L
RadonRadon is a radioactive breakdown product of radium and uranium in soil, rock and water; it is often present in groundwater.6.36 pCi/L
10.2 pCi/L
Yes
1.5 pCi/L
Legal at any levelThis is the Federal Limit. State Limits may be lower.
NOTE: Each dot in the above graph represents one month.
* 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.

Other Detected Contaminants

ContaminantAverage/
Maximum
Result
Health Limit
Exceeded
Legal Limit
Exceeded

Testing History

-Tested      -Detected      -Over Health Guidelines      -Over Legal Limit*
Monochloroacetic acidMonochloroacetic acid is a disinfection byproduct regulated by EPA as one of five haloacetic acids that are formed when chlorine, chloramines or other disinfectants react with organic and inorganic matter in water.0.61 ppb
19.47 ppb
No
70 ppb
No
60 ppb
Dibromoacetic acidDibromoacetic acid is a disinfection byproduct regulated by EPA as one of five haloacetic acids that are formed when chlorine, chloramines or other disinfectants react with organic and inorganic matter in water.0.06 ppb
0.9 ppb
NoNo
60 ppb
VanadiumVanadium is a metal used as an alloying addition to iron & steel; it is discharged from ceramic, glass, textile, photography, metallurgy and rubber industries.1.31 ppb
6.8 ppb
NoLegal at any levelThis is the Federal Limit. State Limits may be lower.
Chlorine dioxideChlorine dioxide is used as drinking water disinfection agent and as a bleaching agent for cellulose, paper pulp, flour and oils; in water, it rapidly decomposes into toxic disinfection byproducts chlorite and chlorate.89.29 ppb
350 ppb
No
800 ppb
Legal at any levelThis is the Federal Limit. State Limits may be lower.
AluminumAluminum is a metal released from metal refineries and mining operations.16.93 ppb
69.67 ppb
No
200 ppb
No
200 ppb
BromideBromide is a naturally occurring element found in surface waters and groundwater and contributes to the formation of toxic tap water disinfection byproducts.71.43 ppb
180 ppb
NoLegal at any levelThis is the Federal Limit. State Limits may be lower.
LithiumLithium is a pollutant from mining and industrial manufacturing of metal alloys, ceramics, and batteries; it occurs naturally in soil and rock.13.88 ppb
40 ppb
NoLegal at any levelThis is the Federal Limit. State Limits may be lower.
ChloromethaneChloromethane is a naturally occuring chemical that forms during combustion of plant material; it may be released from the manufacture of silicone, rubber and pesticides, and also forms as a byproduct of water disinfection.0.07 ppb
0.64 ppb
No
30 ppb
Legal at any levelThis is the Federal Limit. State Limits may be lower.
Mercury (total inorganic)Mercury is a metal from refinery and factory pollution, coal burning, landfill and agricultural runoff and erosion of natural deposits.0.12 ppb
1.05 ppb
No
1.2 ppb
No
2 ppb
ManganeseManganese is a naturally occurring element released from mineral deposits as well as industrial use.2.63 ppb
21 ppb
No
50 ppb
No
50 ppb
ChlorateChlorate is a disinfection byproduct (unregulated chlorine dioxide byproduct), an herbicide and a pollutant from explosives.0.02 ppb
0.17 ppb
NoLegal at any levelThis is the Federal Limit. State Limits may be lower.
Nitrate & nitriteNitrate and nitrite enter water from fertilizer runoff, leaching from septic tanks, and erosion of natural deposits.0.05 ppm
0.22 ppm
No
10 ppm
No
10 ppm
TritiumTritium is a pollutant from commercial nuclear reactors, research reactors and government weapons production plants.122.5 pCi/L
294 pCi/L
NoLegal at any levelThis is the Federal Limit. State Limits may be lower.
Strontium-90Strontium-90 is a radioactive pollutant from nuclear fallout and possibly weapons and power production.0.13 pCi/L
0.2 pCi/L
NoLegal at any levelThis is the Federal Limit. State Limits may be lower.
Combined Uranium (pCi/L)Uranium is a radioactive element commonly found in most rocks; processed ore is used for power generation and weapons manufacture.0.04 pCi/L
0.12 pCi/L
NoNo
15 pCi/L
Gross beta particle activity (pCi/L)Beta particles are a form of radiation frequently associated with nuclear testing and radioactive mineral deposits.0.48 pCi/L
0.96 pCi/L
NoNo
15 pCi/L
NOTE: Each dot in the above graph represents one month.
* 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.

Contaminants Not Detected - 152 chemicals

1,1,1,2-Tetrachloroethane, 1,1,1-Trichloroethane, 1,1,2,2-Tetrachloroethane, 1,1,2-Trichloroethane, 1,1-Dichloroethane, 1,1-Dichloroethylene, 1,1-Dichloropropene, 1,2,3-Trichlorobenzene, 1,2,3-Trichloropropane, 1,2,4-Trichlorobenzene, 1,2,4-Trimethylbenzene, 1,2-Dichloroethane, 1,2-Dichloropropane, 1,3,5-Trimethylbenzene, 1,3-Dichloropropane, 1,3-Dichloropropene, 1,4-Dioxane, 2,2-Dichloropropane, 2,3,7,8-TCDD (Dioxin), 2,4,5-t, 2,4,5-TP (Silvex), 2,4-d, 2-Chloroethylvinyl ether, 3-Hydroxycarbofuran, Alachlor (Lasso), Aldicarb, Aldicarb sulfone, Aldicarb sulfoxide, Aldrin, Aminocarb, Antimony (total), Arsenic (total), Asbestos, Atrazine, Barban, Barium (total), Baygon (Propoxur), Bentazon (Basagran), Benzene, Benzo[a]pyrene, Beryllium (total), bis(2-chloroethyl) ether, Bromacil, Bromate, Bromobenzene, Bromochloromethane, Bromomethane, Butachlor, Carbaryl, Carbofuran, Carbon tetrachloride, Chlordane, Chlorite, Chloroethane, Chlorothalonil (Bravo), Chlorotoluene, Chlorpropham, Chromium (hexavalent), Chromium (total), cis-1,2-Dichloroethylene, Combined Uranium (mg/L), Copper, Cyanide, Dacthal, Dalapon, Di(2-Ethylhexyl) adipate, Diazinon (Spectracide), Dibromomethane, Dicamba, Dichlorodifluoromethane, Dichloromethane (methylene chloride), Dieldrin, Dimethoate, Dinoseb, Diquat, Diuron, Endothall, Endrin, Ethyl-t-butyl ether (ETBE), Ethylbenzene, Fenuron, Fluometuron, Glyphosate, Heptachlor, Heptachlor epoxide, Hexachlorobenzene (HCB), Hexachlorobutadiene, Hexachlorocyclopentadiene, Hydrogen sulfide, Isopropyl ether, Isopropylbenzene, Lindane, Linuron, m- & p- Xylene, m-Dichlorobenzene, m-Xylene, Methiocarb, Methomyl, Methoxychlor, Methyl ethyl ketone, Methyl isobutyl ketone, Metolachlor, Metribuzin, Mexacarbate, Molinate (Ordram), Molybdenum, Monobromoacetic acid, Monochlorobenzene (Chlorobenzene), Monuron, Mtbe, n-Butylbenzene, n-Propylbenzene, Naphthalene, Neburon, Nitrate, Nitrite, o-Chlorotoluene, o-Dichlorobenzene, o-Xylene, Oxamyl (Vydate), p-Chlorotoluene, p-Dichlorobenzene, p-Isopropyltoluene, p-Xylene, Pentachlorophenol, Perchlorate, Picloram, Prometryn, Propachlor, Propham, Radium-226, sec-Butylbenzene, Selenium (total), Siduron, Silver (total), Simazine, Styrene, Tert-Amyl-Methyl Ether, tert-Butylbenzene, Tetrachloroethylene, Thallium (total), Thiobencarb (Bolero), Toluene, Total polychlorinated biphenyls (PCBs), Toxaphene, trans-1,2-Dichloroethylene, trans-1,3-Dichloropropene, Trichloroethylene, Trichlorofluoromethane, Trichlorotrifluoroethane, Vinyl chloride, Xylenes (total)

Pollution Summary

32Total Contaminants Detected (2004 - 2009)

Aluminum, Bromide, Chlorate, Chlorine dioxide, Manganese, Mercury (total inorganic), Nitrate & nitrite, Lithium, Vanadium, Chloromethane, Monochloroacetic acid, Dibromoacetic acid, Tritium, Strontium-90, Combined Uranium (pCi/L), Gross beta particle activity (pCi/L), Cadmium (total), Lead (total), Di(2-ethylhexyl) phthalate, Dichloroacetic acid, Trichloroacetic acid, Total haloacetic acids (HAAs), 1,2-Dibromo-3-chloropropane (DBCP), Chloroform, Bromoform, Bromodichloromethane, Dibromochloromethane, Ethylene dibromide (EDB), Total trihalomethanes (TTHMs), Radon, Radium-228, Alpha particle activity

4Agricultural Pollutants
(pesticides, fertilizer, factory farms)

Chlorate, Nitrate & nitrite, 1,2-Dibromo-3-chloropropane (DBCP), Ethylene dibromide (EDB)

5Sprawl and Urban Pollutants
(road runoff, lawn pesticides, human waste)

Nitrate & nitrite, Lead (total), Cadmium (total), Mercury (total inorganic), Lithium

20Industrial Pollutants

Aluminum, Bromide, Chlorate, Chlorine dioxide, Manganese, Mercury (total inorganic), Nitrate & nitrite, Lithium, Vanadium, Chloromethane, Tritium, Strontium-90, Combined Uranium (pCi/L), Gross beta particle activity (pCi/L), Cadmium (total), Lead (total), Di(2-ethylhexyl) phthalate, Ethylene dibromide (EDB), Radium-228, Alpha particle activity

15Water 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, Di(2-ethylhexyl) phthalate, Cadmium (total), Chloromethane, Chlorine dioxide, Chlorate

13Naturally Occurring
(naturally present but increased for lands denuded by sprawl, agriculture, or industrial development)

Nitrate & nitrite, Lead (total), Manganese, Radium-228, Alpha particle activity, Gross beta particle activity (pCi/L), Combined Uranium (pCi/L), Aluminum, Radon, Bromide, Mercury (total inorganic), Chloromethane, Lithium

10Unregulated Contaminants
EPA has not established a maximum legal limit in tapwater for these contaminants

Bromide, Chlorate, Chlorine dioxide, Lithium, Vanadium, Chloromethane, Tritium, Strontium-90, Lead (total), Radon

EPA Violation Summary

No violations were reported for this system since 2004.

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.