Know Your Environment. Protect Your Health.

Uranium

Mission Creek Water Association

Uranium is a known human carcinogen. The federal legal limit for uranium is set at 30 micrograms per liter (corresponding to parts per billion), but utilities can also report uranium in picocuries per liter (pCi/L), which is a measure of radioactivity in water. EWG translated all uranium results to pCi/L using a conversion factor developed by the EPA. With this conversion approach, the limit of 30 ppb corresponds to 20 pCi/L. Drinking water with this much uranium would cause more than 4.6 cancer cases in a population of 100,000. California set a public health goal for uranium of 0.43 pCi/L. Read More.

Multiple forms of uranium can be detected in water, including uranium-234, uranium-235 and uranium-238. Uranium-234 is the most toxic form of uranium for human health.

 

80

Samples

42

Samples exceeding legal limit (MCL)

51

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
201823.37 pCi/L4422.11 pCi/L - 24.79 pCi/L
201919.61 pCi/L64ND - 45.76 pCi/L
202013.32 pCi/L2310ND - 60.43 pCi/L
202114.27 pCi/L1810ND - 39.06 pCi/L
202235.42 pCi/L9924.05 pCi/L - 47.84 pCi/L
202315.83 pCi/L2014ND - 47.24 pCi/L

pCi/L = picocuries per liter

State, National, and Health Guidelines for Drinking Water

EWG Health Guideline: 0.43 pCi/L

The EWG Health Guideline of 0.43 pCi/L for uranium was defined by the California Office of Environmental Health Hazard Assessment as a public health goal, the level of a drinking water contaminant that does not pose a significant health risk. Three most common uranium isotopes are U-234, U-235 and U-238. All isotopes of uranium are radioactive, and the total radioactivity depends on the ratio of isotopes. This health guideline protects against cancer.

EPA Maximum Contaminant
Level (MCL): 20 pCi/L

pCi/L = picocuries per liter

All test results

Date Lab ID Result
2018-03-27RC1804007900122.91 pCi/L
2018-06-19R19443823.65 pCi/L
2018-09-24R19790224.79 pCi/L
2018-11-14R19939322.11 pCi/L
2019-03-26R20246545.76 pCi/L
2019-06-10R20474124.46 pCi/L
2019-09-24R20914123.99 pCi/L
2019-10-21R210239ND
2019-10-21R210240ND
2019-12-24R111001923.45 pCi/L
2020-01-13R212589ND
2020-01-13R21259023.25 pCi/L
2020-01-13R212593ND
2020-01-13R212592ND
2020-01-13R212591ND
2020-02-13R213372ND
2020-02-17R213453ND
2020-02-17R21345210.92 pCi/L
2020-03-05RC2003038000124.25 pCi/L
2020-06-28R217389ND
2020-06-28RC2007037600127.54 pCi/L
2020-06-28RC2007040754.20 pCi/L
2020-09-09RXOI0183ND
2020-09-19RC2010004800225.46 pCi/L
2020-09-19RC2010004800160.43 pCi/L
2020-09-21R220770ND
2020-12-07R2234880.81 pCi/L
2020-12-07R223487ND
2020-12-07R223485ND
2020-12-07R223484ND
2020-12-07R223483ND
2020-12-21RC2101001000155.14 pCi/L
2020-12-21R22393324.39 pCi/L
2021-03-22RC2103089000134.17 pCi/L
2021-03-22R22633023.38 pCi/L
2021-05-18R22826523.85 pCi/L
2021-05-18R22826438.59 pCi/L
2021-09-27R23353927.34 pCi/L
2021-09-28R23354022.45 pCi/L
2021-10-11R23414339.06 pCi/L
2021-10-11R23414422.18 pCi/L
2021-11-06R202111020804ND
2021-11-06R202111020807ND
2021-11-06R202111020808ND
2021-11-06R202111020806ND
2021-11-06R202111020801ND
2021-11-06R202111020805ND
2021-11-07R202111020802ND
2021-11-07R202111020803ND
2021-11-07R20211102080922.58 pCi/L
2021-12-20R20211203623.21 pCi/L
2022-03-07R23861526.00 pCi/L
2022-03-07R23861438.66 pCi/L
2022-05-23R24139438.53 pCi/L
2022-05-23R24139524.79 pCi/L
2022-07-28R202207077347.17 pCi/L
2022-07-28R202207077425.13 pCi/L
2022-09-26R24749047.84 pCi/L
2022-10-26R24880124.05 pCi/L
2022-10-26R24880246.63 pCi/L
2023-03-06R25261225.86 pCi/L
2023-03-06R25261145.90 pCi/L
2023-06-28R2566863.03 pCi/L
2023-06-28R2566814.72 pCi/L
2023-06-28R2566820.88 pCi/L
2023-06-28R256684ND
2023-06-30R25681044.89 pCi/L
2023-06-30R25681124.86 pCi/L
2023-09-25R26043447.24 pCi/L
2023-09-25R26043525.59 pCi/L
2023-11-28R202311039201ND
2023-11-28R202311039202ND
2023-11-28R2023110392035.17 pCi/L
2023-11-28R202311039204ND
2023-11-28R20231103920516.08 pCi/L
2023-11-28R202311039206ND
2023-12-10R263165ND
2023-12-19R26334925.06 pCi/L
2023-12-19R26334841.81 pCi/L
2023-12-26R2635475.48 pCi/L