The Power of Information

National Drinking Water Database


City of Modesto - Modesto, CA


Serves 190,106 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.
21 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.
9 chemicals
0.5
Pollutants FoundThe total number of contaminants detected since 2004, according to data provided by the state water agency.
37 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.
68,482 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*
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.0.07 ppb
0.39 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
0.2 ppb
Alpha particle activityAlpha particles are a form of radiation released from mining waste pollutants and natural sources.8.11 pCi/L
29.1 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
Yes
15 pCi/L
Combined Uranium (pCi/L)Uranium is a radioactive element commonly found in most rocks; processed ore is used for power generation and weapons manufacture.7.5 pCi/L
34 pCi/L
YesYes
15 pCi/L
TetrachloroethyleneTetrachloroethylene (perc) is a common soil and groundwater contaminant used in dry cleaning and as a solvent in automotive and metalworking factories and other industries.0.69 ppb
12 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
5 ppb
Arsenic (total)Arsenic contaminates drinking water due to mining runoff, erosion of natural deposits, emissions from glass and electronics processing and the use of arsenical compounds as wood preservatives and pesticides.6.07 ppb
14 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
10 ppb
ManganeseManganese is a naturally occurring element released from mineral deposits as well as industrial use.41.41 ppb
205 ppb
Yes
50 ppb
Yes
50 ppb
TrichloroethyleneTrichloroethylene is used to remove grease from fabricated metal parts and in the production of some textiles; this pollutant comes from metal degreasing sites, metal finishing and rubber processing industries.0.77 ppb
9 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
5 ppb
Combined Uranium (mg/L)Uranium is a radioactive element commonly found in most rocks; processed uranium ore is used for power generation and weapons manufacture.19.24 ppb
36 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
30 ppb
NitrateNitrate enters drinking water sources from fertilizer runoff, leaching septic tanks, and erosion of natural deposits; it is also emitted by chemical, petrochemical and metal-finishing industries.5.05 ppm
10.26 ppm
Yes
10 ppm
Yes
10 ppm
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.0.92 ppb
12 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
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.0.32 ppb
5 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.0.23 ppb
6.7 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.3.02 ppb
33 ppb
Yes
5.7 ppb
No
80 ppb
Total trihalomethanes (TTHMs)Total trihalomethanes constitute the sum of four disinfection byproducts: chloroform, bromodichloromethane, dibromochloromethane, and bromoform.4.6 ppb
47 ppb
Yes
9.8 ppb
No
80 ppb
Radium-228Radium-228 is a radioactive element usually found around uranium deposits.0.08 pCi/L
1.43 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
Radium-226Radium-226 is a radioactive element usually found around uranium deposits.0.03 pCi/L
0.21 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
1,1,2-Trichloroethane1,1,2-Trichloroethane is used in production of synthetic fibers, plastic wraps and adhesives; it is released as a pollutant from various chemical manufacturing factories.<0.01 ppb
1 ppb
Yes
0.3 ppb
No
5 ppb
Dichloromethane (methylene chloride)Dichloromethane is a widely-used paint remover, solvent and metal degreasing agent; it is discharged into the environment from the manufacture of chemicals, textiles, electronics, metals and plastics, pharmaceuticals and pesticides.<0.01 ppb
0.28 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
5 ppb
Combined Radium (-226 & -228)Radium is a radioactive element usually found around uranium deposits.0.28 pCi/L
0.4 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
Carbon tetrachlorideCarbon tetrachloride is an industrial solvent and refrigerant released as a pollutant from various chemical plants and the petroleum refining industry.<0.01 ppb
1.43 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
5 ppb
n-Nitrosodimethylaminen-Nitrosodimethylamine is a carcinogenic water contaminant released from various industrial processes; it also forms in drinking water as disinfection byproduct of chloramination and from agricultural runoff.<0.01 ppb
<0.01 ppb
Yes
<0.01 ppb
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*
Nitrate & nitriteNitrate and nitrite enter water from fertilizer runoff, leaching from septic tanks, and erosion of natural deposits.0.06 ppm
6.02 ppm
No
10 ppm
No
10 ppm
NitriteNitrite is a chemical that enters water from fertilizer runoff, leaching septic tanks, and erosion of natural deposits.<0.01 ppm
<0.01 ppm
No
1 ppm
No
1 ppm
Barium (total)Barium is a mineral that enters drinking water through drilling and mining waste runoff, discharges from chemical industries and erosion of natural deposits.82.6 ppb
350 ppb
No
700 ppb
No
2000 ppb
TrichlorotrifluoroethaneTrichlorotrifluoroethane (Freon 113) is used in industrial applications such as a degreasing or dry cleaning solvent, refrigerant, fire extinguisher component and chemical intermediate; production in the U.S. has been banned since 1996.3.4 ppb
42 ppb
No
4000 ppb
Legal at any levelThis is the Federal Limit. State Limits may be lower.
Selenium (total)Selenium is a naturally occurring element that contaminates water due to mining or petrolum refining, fly-ash from coal-burning power plants, and irrigation of arid farmland soils high in selenium.0.93 ppb
10 ppb
No
50 ppb
No
50 ppb
DichlorodifluoromethaneDichlorodifluoromethane (Freon 12) is a chlorofluorocarbon refrigerant and aerosol spray propellant; it was banned under the Montreal Protocol as of 2000 because of its ozone-depleting properties.0.03 ppb
1.2 ppb
No
1000 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.4 ppb
156.67 ppb
No
200 ppb
No
200 ppb
Chromium (total)Chromium is a metal that pollutes drinking water due to discharge from steel and pulp mills and erosion of natural deposits.0.24 ppb
11 ppb
No
100 ppb
No
100 ppb
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.0.02 ppb
4.25 ppb
No
30 ppb
Legal at any levelThis is the Federal Limit. State Limits may be lower.
1,1-DichloroethyleneIndustrial chemical pollutant from manufacture of adhesives, synthetic fibers, refrigerants and plastic wraps.<0.01 ppb
0.9 ppb
No
7 ppb
No
7 ppb
BromomethaneBromomethane is a pesticide used for soil, grain, indoor air and other applications, and a solvent used to extract vegetable and seed oils.<0.01 ppb
0.12 ppb
No
10 ppb
Legal at any levelThis is the Federal Limit. State Limits may be lower.
TrichlorofluoromethaneTrichlorofluoromethane (Freon 11) is a refrigerant, solvent, chemical intermediate and halocarbon aerosol that was banned in 2000 under the Montreal Protocol because of its ozone-depleting properties.0.08 ppb
17.5 ppb
No
700 ppb
Legal at any levelThis is the Federal Limit. State Limits may be lower.
IsopropylbenzeneIsopropylbenzene is an intermediate in industrial chemical production, and is also used as a thinner for paints and enamels and a component of fuel; it is released from petroleum refining, evaporation and combustion.<0.01 ppb
0.29 ppb
No
700 ppb
Legal at any levelThis is the Federal Limit. State Limits may be lower.
Antimony (total)Antimony is a metal that enters water from petroleum refinery pollution, fire retardants, ceramics, electronics and solder.0.03 ppb
3 ppb
No
5.6 ppb
No
6 ppb
Methyl ethyl ketoneMethyl ethyl ketone is a synthetic chemical used as a solvent for paints, coatings, adhesives, printing inks, and other industrial and consumer goods; it occurs naturally in some vegetation and forms during ozonation of drinking water. 0.09 ppb
5.5 ppb
No
4000 ppb
Legal at any levelThis is the Federal Limit. State Limits may be lower.
Gross beta particle activity (pCi/L)Beta particles are a form of radiation frequently associated with nuclear testing and radioactive mineral deposits.1.28 pCi/L
5.1 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 - 139 chemicals

1,1,1,2-Tetrachloroethane, 1,1,1-Trichloroethane, 1,1,2,2-Tetrachloroethane, 1,1-Dichloroethane, 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, 1,3-dinitrobenzene, 2,2',4,4',5,5'-hexabromobiphenyl (hbb), 2,2',4,4',5,5'-hexabromodiphenyl Ether, 2,2',4,4',5-pentabromodiphenyl Ether, 2,2',4,4',6-pentabromodiphenyl Ether, 2,2',4,4'-tetrabromodiphenyl Ether, 2,2-Dichloropropane, 2,4,5-t, 2,4,5-TP (Silvex), 2,4,6-trinitrotoluene (tnt), 2,4-d, 2-Chloroethylvinyl ether, 3-Hydroxycarbofuran, Acetochlor, Acetochlor Ethane Sulfonic Acid, Acetochlor Oxanilic Acid, Acetone, Alachlor (Lasso), Alachlor Ethane Sulfonic Acid, Alachlor Oxanilic Acid, Aldicarb, Aldicarb sulfone, Aldicarb sulfoxide, Aldrin, Asbestos, Atrazine, Bentazon (Basagran), Benzene, Benzo[a]pyrene, Beryllium (total), Bromacil, Bromobenzene, Bromochloromethane, Butachlor, Cadmium (total), Carbaryl, Carbofuran, Chlordane, Chloroethane, Chlorothalonil (Bravo), cis-1,2-Dichloroethylene, cis-1,3-Dichloropropene, Copper, Cyanide, Dalapon, Di(2-Ethylhexyl) adipate, Di(2-ethylhexyl) phthalate, Diazinon (Spectracide), Dibromomethane, Dicamba, Dieldrin, Dimethoate, Dinoseb, Diquat, Diuron, Endothall, Endrin, Ethyl-t-butyl ether (ETBE), Ethylbenzene, Ethylene dibromide (EDB), Glyphosate, Heptachlor, Heptachlor epoxide, Hexachlorobenzene (HCB), Hexachlorobutadiene, Hexachlorocyclopentadiene, Hexachloroethane, Isopropyl ether, Lead (total), Lindane, m- & p- Xylene, m-Dichlorobenzene, m-Xylene, Mercury (total inorganic), Methomyl, Methoxychlor, Methyl isobutyl ketone, Metolachlor, Metolachlor Ethane Sulfonic Acid, Metolachlor Oxanilic Acid, Metribuzin, Molinate (Ordram), Monochlorobenzene (Chlorobenzene), Mtbe, n-Butylbenzene, n-Nitroso di-N-Propylamine, N-nitrosodi-n-butylamine (ndba), N-nitrosomethylethylamine (nmea), N-nitrosopiperidine (npip), N-nitrosopyrrolidine (npyr), n-Propylbenzene, Naphthalene, Nitrobenzene, o-Chlorotoluene, o-Dichlorobenzene, o-Xylene, Oxamyl (Vydate), p-Chlorotoluene, p-Dichlorobenzene, p-Isopropyltoluene, p-Xylene, Pentachlorophenol, Perchlorate, Picloram, Prometryn, Propachlor, Rdx (hexahydro-1,3,5-trinitro-1,3,5-triazine), sec-Butylbenzene, Silver (total), Simazine, Styrene, Terbufos Sulfone, Tert-Amyl-Methyl Ether, Tert-Butyl Alcohol, tert-Butylbenzene, Thallium (total), Thiobencarb (Bolero), Toluene, Total polychlorinated biphenyls (PCBs), Toxaphene, trans-1,2-Dichloroethylene, trans-1,3-Dichloropropene, Trifluralin, Vinyl chloride, Xylenes (total)

Pollution Summary

37Total Contaminants Detected (2004 - 2009)

Aluminum, Barium (total), Chromium (total), Nitrate & nitrite, Nitrite, Selenium (total), Antimony (total), Chloromethane, Dichlorodifluoromethane, Bromomethane, Trichlorofluoromethane, Methyl ethyl ketone, Trichlorotrifluoroethane, 1,1-Dichloroethylene, Isopropylbenzene, Gross beta particle activity (pCi/L), Arsenic (total), Manganese, Nitrate, n-Nitrosodimethylamine, 1,2-Dibromo-3-chloropropane (DBCP), Chloroform, Bromoform, Bromodichloromethane, Dibromochloromethane, Total trihalomethanes (TTHMs), Dichloromethane (methylene chloride), Carbon tetrachloride, Trichloroethylene, 1,1,2-Trichloroethane, Tetrachloroethylene, Combined Uranium (mg/L), Combined Radium (-226 & -228), Radium-226, Radium-228, Alpha particle activity, Combined Uranium (pCi/L)

8Agricultural Pollutants
(pesticides, fertilizer, factory farms)

Nitrate & nitrite, Nitrite, Selenium (total), Bromomethane, Arsenic (total), Nitrate, n-Nitrosodimethylamine, 1,2-Dibromo-3-chloropropane (DBCP)

10Sprawl and Urban Pollutants
(road runoff, lawn pesticides, human waste)

Nitrate, Nitrate & nitrite, Arsenic (total), Tetrachloroethylene, Nitrite, Antimony (total), Dichloromethane (methylene chloride), Trichlorofluoromethane, Methyl ethyl ketone, Trichlorotrifluoroethane

30Industrial Pollutants

Aluminum, Barium (total), Chromium (total), Nitrate & nitrite, Nitrite, Selenium (total), Antimony (total), Chloromethane, Dichlorodifluoromethane, Trichlorofluoromethane, Methyl ethyl ketone, Trichlorotrifluoroethane, 1,1-Dichloroethylene, Isopropylbenzene, Gross beta particle activity (pCi/L), Arsenic (total), Manganese, Nitrate, n-Nitrosodimethylamine, Dichloromethane (methylene chloride), Carbon tetrachloride, Trichloroethylene, 1,1,2-Trichloroethane, Tetrachloroethylene, Combined Uranium (mg/L), Combined Radium (-226 & -228), Radium-226, Radium-228, Alpha particle activity, Combined Uranium (pCi/L)

7Water Treatment and Distribution Byproducts
(pipes and fixtures, treatment chemicals and byproducts)

Total trihalomethanes (TTHMs), Chloroform, Bromodichloromethane, Dibromochloromethane, Bromoform, Chloromethane, n-Nitrosodimethylamine

17Naturally Occurring
(naturally present but increased for lands denuded by sprawl, agriculture, or industrial development)

Nitrate, Nitrate & nitrite, Barium (total), Arsenic (total), Manganese, Radium-228, Radium-226, Alpha particle activity, Combined Radium (-226 & -228), Gross beta particle activity (pCi/L), Combined Uranium (pCi/L), Chromium (total), Combined Uranium (mg/L), Aluminum, Selenium (total), Nitrite, Chloromethane

8Unregulated Contaminants
EPA has not established a maximum legal limit in tapwater for these contaminants

Chloromethane, Dichlorodifluoromethane, Bromomethane, Trichlorofluoromethane, Methyl ethyl ketone, Trichlorotrifluoroethane, Isopropylbenzene, n-Nitrosodimethylamine

EPA Violation Summary

Violation CategoryNumber of Violations
MCL and Treatment
(click see violations)
1

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.