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EWG's Tap Water Database — 2019 UPDATE

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Uranium

Tempe Water Supply Corporation 1

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.

 

44

Samples

0

Samples exceeding legal limit (MCL)

0

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
2012ND40ND
2013ND70ND
2014ND70ND
2015ND90ND
2016ND90ND
2017ND80ND

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
2012-02-29AB82665ND
2012-04-17AB87050ND
2012-09-12AC00659ND
2012-12-11AC06498ND
2013-02-26AC11525ND
2013-02-26AC11523ND
2013-06-14AC22197ND
2013-08-07AC27034ND
2013-08-07AC27036ND
2013-11-07AC34548ND
2013-11-07AC34546ND
2014-01-15AC38984ND
2014-01-15AC38986ND
2014-04-16AC50793ND
2014-04-16AC50794ND
2014-09-08AC66024ND
2014-12-19AC75604ND
2014-12-19AC75611ND
2015-02-24AC81621ND
2015-02-24AC81620ND
2015-02-24AC81622ND
2015-06-02AC94102ND
2015-06-02AC94104ND
2015-08-12AD03776ND
2015-08-12AD03775ND
2015-12-03AD15356ND
2015-12-03AD15358ND
2016-02-25AD25654ND
2016-02-25AD25653ND
2016-03-31AD31402ND
2016-06-07AD39534ND
2016-06-07AD39535ND
2016-09-12AD48758ND
2016-09-12AD48759ND
2016-11-15AD57957ND
2016-11-15AD57958ND
2017-02-15AD70806ND
2017-02-15AD70805ND
2017-06-01AD86335ND
2017-06-01AD86337ND
2017-09-14AD96205ND
2017-09-14AD96206ND
2017-11-07AE03801ND
2017-11-07AE03802ND