The Power of Information

National Drinking Water Database


Benzene in California


Benzene is a petroleum chemical that contaminates drinking water due to emissions from petroleum and chemical industries, leaching landfills and gas storage tanks. [read more]

The Most Polluted Communities in California

14 water utilities reported detecting Benzene in tap water since 2004, according to EWG's analysis of water quality data supplied by state water agencies

Ranked by highest average Benzene level

RankSystem Population Served Positive test results of total reported tests Average Level
(Range)
1Manana Woods Mutual Water Co
Scotts Valley, CA
3504 of 43.38 ppb
(1.9 to 5.8 ppb)
2Riverside Mobile Home Park
Walnut Grove, CA
551 of 31 ppb
(0 to 3 ppb)
3Cuyamaca Water District
Julian, CA
2001 of 20.8 ppb
(0 to 1.6 ppb)
4Linda County Water District
Marysville, CA
12,00056 of 670.68 ppb
(0 to 2.05 ppb)
5Arvin Community Services Dist
Arvin, CA
11,84711 of 260.59 ppb
(0 to 2.1 ppb)
6Paradise Ranch Mhp C/O Santiago Assoc.
Castaic, CA
2041 of 30.33 ppb
(0 to 1 ppb)
7Hope Foundation/Moriah Heights
Plymouth, CA
3001 of 40.25 ppb
(0 to 1 ppb)
8City of Norco
Norco, CA
25,9091 of 20.19 ppb
(0 to 0.38 ppb)
9Madera County M.D. #10a - Madera Ranchos
Madera, CA
2,7501 of 30.08 ppb
(0 to 0.25 ppb)
10Imperial Irrigation District
Imperial, CA
3,3031 of 50.07 ppb
(0 to 0.34 ppb)

Health Based Limits for Benzene

StandardDescriptionLevel
Maximum Contaminant Limit Goal (MCLG)A 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
California Public Health GoalsDefined by the State of California Office of Environmental Health Hazard Assessment (OEHHA) as the level of contaminant that is allowed in drinking water. For acutely toxic substances, levels are set at which scientific evidence indicates that no known or anticipated adverse effects on health will occur, plus an adequate margin-of safety. PHGs for carcinogens or other substances which can cause chronic disease shall be based solely on health effects without regard to cost impacts and shall be set at levels which OEHHA has determined do not pose any significant risk to health.0.15 ppb
One in one million (10-6) Cancer RiskThe concentration of a chemical in drinking water corresponding to an excess estimated lifetime cancer risk of 1 in 1,000,000. Source: U.S. Environmental Protection Agency.1 ppb
EPA Human Health Water Quality CriteriaWater quality criteria set by the US EPA provide guidance for states and tribes authorized to establish water quality standards under the Clean Water Act (CWA) to protect human health. These are non-enforceable standards based upon exposure by both drinking water and the contribution of water contamination to other consumed foods. Source: U.S. Environmental Protection Agency.2.2 ppb
Maximum Contaminant Limit (MCL)The enforceable standard which defines the highest level of a contaminant that is allowed in drinking water. MCLs are set as close to health-based limits (Maximum Contaminant Level Goals, or MCLGs) as feasible using the best available analytical and treatment technologies and taking cost into consideration. Source: U.S. Environmental Protection Agency.5 ppb
One in ten thousand (10-4) Cancer RiskThe concentration of a chemical in drinking water corresponding to an excess estimated lifetime cancer risk of 1 in 10,000. Source: U.S. Environmental Protection Agency.100 ppb
Drinking Water Equivalent LevelA lifetime exposure concentration protective of adverse, noncarcinogenic health effects, that assumes all of the exposure to a contaminant is from drinking water. Source: U.S. Environmental Protection Agency.100 ppb
Children's health-based limit for 1-day exposureConcentration of a chemical in drinking water that is not expected to cause any adverse, noncarcinogenic health effects for up to one day of exposure. The One-Day health-based limit (or Health Advisory, HA) is typically set to protect a 10-kg child consuming 1 liter of water per day. Source: U.S. Environmental Protection Agency.200 ppb
Children's health-based limit for 10-day exposureConcentration of a chemical in drinking water that is not expected to cause any adverse, noncarcinogenic effects for up to ten days of exposure. The Ten-Day health-based limit (or Health Advisory, HA) is typically set to protect a 10-kg child consuming 1 liter of water per day. Source: U.S. Environmental Protection Agency.200 ppb

Violation Summary for Benzene in 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 regularly25