The Power of Information

National Drinking Water Database

Bromate in California

Bromate is a carcinogenic disinfection byproduct of ozonation formed when source waters contain high levels of natural bromide; it can also form following water treatment with chlorine dioxide or hypochlorite. [read more]

The Most Polluted Communities in California

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

Ranked by highest average Bromate level

RankSystem Population Served Positive test results of total reported tests Average Level
1Bassi Ranch Mutual Water Co.
San Luis Obispo, CA
854 of 418.28 ppb
(5.1 to 29 ppb)
2Golden State Water Company - Bay Point
Rancho Cordova, CA
16,7152 of 29.15 ppb
(6.3 to 12 ppb)
3Mesa Consolidated Wd
Costa Mesa, CA
108,724154 of 2394.06 ppb
(0 to 20 ppb)
4City of Antioch
Antioch, CA
100,9453 of 62.96 ppb
(0 to 8.6 ppb)
5Randall-Bold Water Treatment Plant
Oakley, Ca, CA
30,00021 of 621.02 ppb
(0 to 9.2 ppb)
6City of Martinez
Martinez, CA
36,0007 of 570.81 ppb
(0 to 10 ppb)
7Diablo Water District
Oakley, CA
33,25017 of 400.76 ppb
(0 to 9.2 ppb)
8Contra Costa Water District
Concord, CA
200,0004 of 620.5 ppb
(0 to 12 ppb)
9Los Angeles Department of Water and Power
Los Angeles, CA
3,828,70041 of 840.24 ppb
(0 to 7.38 ppb)
10City of Fresno Water Division
Fresno, CA
390,3503 of 490.2 ppb
(0 to 10 ppb)

Health Based Limits for Bromate

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
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.0.05 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.5 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.10 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.140 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

Violation Summary for Bromate 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
Monitoring and Reporting Disinfection Byproduct Rule3