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EWG's Tap Water Database — 2021 UPDATE

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Uranium

Hillview Water Co-raymond

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.

MORE ABOUT THIS CONTAMINANT

 

156

Samples

87

Samples exceeding legal limit (MCL)

111

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
201439.22 pCi/L11112.30 pCi/L - 78.00 pCi/L
201545.07 pCi/L993.20 pCi/L - 74.00 pCi/L
201643.00 pCi/L9919.00 pCi/L - 71.00 pCi/L
201741.60 pCi/L101020.00 pCi/L - 63.00 pCi/L
201823.60 pCi/L2117ND - 56.00 pCi/L
201915.49 pCi/L9655ND - 38.00 pCi/L

pCi/L = picocuries per liter

State and national drinking water standards and health guidelines

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
2014-02-195810-010-090551.00 pCi/L
2014-02-195810-016-095074.00 pCi/L
2014-03-045810-004-07302.30 pCi/L
2014-05-225810-010-111019.00 pCi/L
2014-05-225810-016-121043.00 pCi/L
2014-06-245810-006-15153.20 pCi/L
2014-07-305810-006-10182.90 pCi/L
2014-08-185810-010-110053.00 pCi/L
2014-08-185810-016-114158.00 pCi/L
2014-11-175810-010-104347.00 pCi/L
2014-11-175810-016-111578.00 pCi/L
2015-02-095810-010-102445.00 pCi/L
2015-02-095810-016-11303.20 pCi/L
2015-05-195810-010-100941.00 pCi/L
2015-05-195810-016-110068.00 pCi/L
2015-07-285810-019-12203.40 pCi/L
2015-08-185810-010-105354.00 pCi/L
2015-08-185810-016-120666.00 pCi/L
2015-11-105810-010-105451.00 pCi/L
2015-11-105810-016-113974.00 pCi/L
2016-02-095810-010-102536.00 pCi/L
2016-02-095810-016-114659.00 pCi/L
2016-05-235810-010-104923.00 pCi/L
2016-05-235810-016-114671.00 pCi/L
2016-08-095810-010-110938.00 pCi/L
2016-08-095810-016-115348.00 pCi/L
2016-10-185810-019-120719.00 pCi/L
2016-11-085810-010-121844.00 pCi/L
2016-11-085810-016-132549.00 pCi/L
2017-01-165810-019-120052.00 pCi/L
2017-02-145810-010-110742.00 pCi/L
2017-02-145810-016-114520.00 pCi/L
2017-04-115810-019-111454.00 pCi/L
2017-05-165810-010-101141.00 pCi/L
2017-05-165810-016-103547.00 pCi/L
2017-08-085810-010-112263.00 pCi/L
2017-08-085810-016-120941.00 pCi/L
2017-11-075810-010-114726.00 pCi/L
2017-11-075810-016-122130.00 pCi/L
2018-02-065810-010-093444.00 pCi/L
2018-02-065810-016-113056.00 pCi/L
2018-04-035810-016-151053.00 pCi/L
2018-05-085810-010-125223.00 pCi/L
2018-05-085810-016-124542.00 pCi/L
2018-08-015810-010-101637.00 pCi/L
2018-08-015810-016-104135.00 pCi/L
2018-08-015810-018-10406.90 pCi/L
2018-08-015810-020-10209.90 pCi/L
2018-08-285810-019-150022.00 pCi/L
2018-10-025810-019-155519.00 pCi/L
2018-11-065810-010-10448.70 pCi/L
2018-11-065810-016-093052.00 pCi/L
2018-12-045810-021-131523.00 pCi/L
2018-12-045810-022-1327ND
2018-12-125810-021-101520.00 pCi/L
2018-12-125810-022-1035ND
2018-12-185810-021-150619.00 pCi/L
2018-12-185810-022-1530ND
2018-12-275810-021-110725.00 pCi/L
2018-12-275810-022-1110ND
2019-01-025810-021-151520.00 pCi/L
2019-01-025810-022-1517ND
2019-01-085810-021-141919.00 pCi/L
2019-01-085810-022-1428ND
2019-01-095810-019-150034.00 pCi/L
2019-01-155810-021-141226.00 pCi/L
2019-01-155810-022-1440ND
2019-01-255810-021-115220.00 pCi/L
2019-01-255810-022-1210ND
2019-01-295810-021-111123.00 pCi/L
2019-01-295810-022-1124ND
2019-02-065810-010-154211.00 pCi/L
2019-02-065810-016-153234.00 pCi/L
2019-02-065810-018-152219.00 pCi/L
2019-02-065810-020-151424.00 pCi/L
2019-02-075810-021-091218.00 pCi/L
2019-02-075810-022-0915ND
2019-02-125810-021-145030.00 pCi/L
2019-02-125810-022-1505ND
2019-02-205810-021-134018.00 pCi/L
2019-02-205810-022-1400ND
2019-02-265810-021-132024.00 pCi/L
2019-02-265810-022-1353ND
2019-03-065810-021-154522.00 pCi/L
2019-03-065810-022-15332.50 pCi/L
2019-03-125810-021-135025.00 pCi/L
2019-03-125810-022-1358ND
2019-03-195810-021-143028.00 pCi/L
2019-03-195810-022-1445ND
2019-03-265810-021-152025.00 pCi/L
2019-03-265810-022-1535ND
2019-04-025810-021-111823.00 pCi/L
2019-04-025810-022-1215ND
2019-04-095810-021-140026.00 pCi/L
2019-04-095810-022-1406ND
2019-04-165810-021-151527.00 pCi/L
2019-04-165810-022-1527ND
2019-04-235810-021-152526.00 pCi/L
2019-04-235810-022-1613ND
2019-04-305810-021-150024.00 pCi/L
2019-04-305810-022-1620ND
2019-05-075810-021-153526.00 pCi/L
2019-05-075810-022-1554ND
2019-05-145810-021-160527.00 pCi/L
2019-05-145810-022-1608ND
2019-05-215810-021-153326.00 pCi/L
2019-05-215810-022-1523ND
2019-05-285810-021-152325.00 pCi/L
2019-05-285810-022-1540ND
2019-06-045810-021-161032.00 pCi/L
2019-06-045810-022-1619ND
2019-06-115810-021-151730.00 pCi/L
2019-06-115810-022-1531ND
2019-06-185810-021-152226.00 pCi/L
2019-06-185810-022-1529ND
2019-06-255810-021-115129.00 pCi/L
2019-06-255810-022-1150ND
2019-07-025810-021-115036.00 pCi/L
2019-07-025810-022-1204ND
2019-07-095810-021-162333.00 pCi/L
2019-07-095810-022-1637ND
2019-07-165810-021-050034.00 pCi/L
2019-07-165810-022-0509ND
2019-07-225810-020-101037.00 pCi/L
2019-07-245810-021-081938.00 pCi/L
2019-07-245810-022-0821ND
2019-07-305810-021-115030.00 pCi/L
2019-07-305810-022-1232ND
2019-08-065810-021-131530.00 pCi/L
2019-08-065810-022-1324ND
2019-08-135810-021-152230.00 pCi/L
2019-08-135810-022-1526ND
2019-08-205810-021-155230.00 pCi/L
2019-08-205810-022-1553ND
2019-08-275810-021-135132.00 pCi/L
2019-08-275810-022-1347ND
2019-08-295810-016-112235.00 pCi/L
2019-09-035810-019-110231.00 pCi/L
2019-09-035810-021-152729.00 pCi/L
2019-09-035810-022-1526ND
2019-09-105810-021-142835.00 pCi/L
2019-09-105810-022-1429ND
2019-09-175810-021-103031.00 pCi/L
2019-09-175810-022-1030ND
2019-09-245810-021-151835.00 pCi/L
2019-09-245810-022-1520ND
2019-10-015810-021-142834.00 pCi/L
2019-10-015810-022-1430ND
2019-10-215810-018-093018.00 pCi/L
2019-10-215810-020-094536.00 pCi/L
2019-11-055810-021-135929.00 pCi/L
2019-11-055810-022-1340ND
2019-11-195810-016-133034.00 pCi/L
2019-11-195810-019-132213.00 pCi/L
2019-12-035810-021-104528.00 pCi/L
2019-12-035810-022-1050ND