The Power of Information

National Drinking Water Database

Combined Uranium (mg/L) in California

Uranium is a radioactive element commonly found in most rocks; processed uranium ore is used for power generation and weapons manufacture. [read more]

The Most Polluted Communities in California

157 water utilities reported detecting Combined Uranium (mg/L) in tap water since 2004, according to EWG's analysis of water quality data supplied by state water agencies

Ranked by highest average Combined Uranium (mg/L) level

RankSystem Population Served Positive test results of total reported tests Average Level
1Kern County Water Agency
Bakersfield, CA
01 of 164.1 ppb
(64.1 ppb)
2Md#07 Marina View Heights
Bass Lake, CA
2002 of 262.5 ppb
(40 to 85 ppb)
3Hillview Wc-Oakhurst/Sierra Lakes
Oakhurst, CA
2,96159 of 5950.03 ppb
(1.2 to 88.67 ppb)
4Md#06 Lake Shore Park
Bass Lake, CA
1303 of 347.75 ppb
(11.05 to 82 ppb)
5Sierra Linda Mutual Water Co
North Fork, CA
2254 of 447.65 ppb
(39.3 to 54.53 ppb)
6Cascadel Mutual Water System
North Fork, CA
3004 of 432.49 ppb
(10.53 to 52.35 ppb)
7Hollister Ranch Estates
Oakland, CA
1002 of 232 ppb
(28 to 36 ppb)
8Mahal Apartments
Firebaugh, CA
504 of 431.4 ppb
(26.3 to 35.3 ppb)
9Two Twenty Four Mobile Home Pk
North Fork, CA
304 of 430.8 ppb
(5.4 to 49.5 ppb)
10Mission Springs Wd
Desert Hot Springs, CA
26,0001 of 130 ppb
(30 ppb)

Health Based Limits for Combined Uranium (mg/L)

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.0.5 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.20 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.30 ppb

Violation Summary for Combined Uranium (mg/L) 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
Over maximum contaminant level, Average11
Failure to monitor regularly5
Over maximum contaminant level, Single Sample4