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National Drinking Water Database

National Drinking Water Database - Chemical Contaminants


Status: Regulated - EPA has established a maximum legal limit in tapwater for this contaminant.

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]

Found above
health guidelines
Found above
legal limit
Water utilities
People Served

Bromate Exposure by State

Water utilities in 18 states have reported detecting Bromate in treated tap water since 2004, according to EWG's analysis of water quality data supplied by state water agencies.

StateWater Suppliers with Bromate contaminationWater suppliers reporting Bromate above health-based limits
North Dakota190,599190,599
North Carolina183,210183,210
New Mexico29,63129,631

The Most Polluted Communities

83 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)
3City of Fargo
Fargo, ND
90,5997 of 76.89 ppb
(5 to 9.3 ppb)
Findlay, IL
80036 of 556.63 ppb
(0 to 24 ppb)
5Blacksburg-Christiansburg-Vpi Water Auth
Blacksburg, VA
8,3001 of 16.57 ppb
(6.57 ppb)
6Las Vegas Valley Water District
Las Vegas, NV
1,181,2631 of 16.35 ppb
(6.35 ppb)
7City of North Las Vegas Utilities Department
N Las Vegas, NV
282,6001 of 16.35 ppb
(6.35 ppb)
8Big Bend Water District
Laughlin, NV
8,30017 of 245.58 ppb
(0 to 15 ppb)
9Windmill Water
Edgewood, NM
1,53910 of 105.11 ppb
(5 to 6.1 ppb)
10Indian Hills Gid
Carson City, NV
5,8002 of 25 ppb
(4 to 6 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

Testing Summary for Bromate

Are tests routinely required for Bromate by federal law?Yes
Water suppliers reporting tests for Bromate (2004-2009):235 of 47,576
Average testing rate for water supplier reporting tests (2004-2009):4.2 per year

Violation Summary for Bromate

Data from the U.S. Environmental Protection Agency includes the following violations of federal standards for Bromate since 2004

Maximum Contaminant Level Exceedance Violations12
Monitoring Violations0
Reporting Violations0