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EWG's Tap Water Database — 2019 UPDATE

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Uranium

City of Houston

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.

 

57

Samples

0

Samples exceeding legal limit (MCL)

30

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
2012N/A00N/A
20132.55 pCi/L112.55 pCi/L
20143.10 pCi/L1611ND - 7.64 pCi/L
20150.60 pCi/L123ND - 5.23 pCi/L
2016N/A00N/A
20171.72 pCi/L2815ND - 11.32 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
2013-12-17AC377552.55 pCi/L
2014-04-16AC50792ND
2014-04-17AC510317.04 pCi/L
2014-04-17AC510296.77 pCi/L
2014-04-17AC51030ND
2014-04-17AC510283.15 pCi/L
2014-06-03AC55781ND
2014-08-14AC636542.61 pCi/L
2014-08-14AC63653ND
2014-10-08AC691583.69 pCi/L
2014-10-08AC691605.16 pCi/L
2014-10-08AC691597.64 pCi/L
2014-10-09AC693451.27 pCi/L
2014-12-09AC741764.15 pCi/L
2014-12-09AC74175ND
2014-12-18AC754295.96 pCi/L
2014-12-18AC754282.21 pCi/L
2015-03-04AC82844ND
2015-03-05AC828655.23 pCi/L
2015-06-04AC94580ND
2015-06-04AC94582ND
2015-06-04AC945811.01 pCi/L
2015-06-04AC94583ND
2015-07-21AD00334ND
2015-07-21AD00333ND
2015-10-22AD11458ND
2015-10-22AD11459ND
2015-11-12AD133160.94 pCi/L
2015-11-16AD13540ND
2017-01-26AD670701.41 pCi/L
2017-01-26AD670714.76 pCi/L
2017-02-28AD72393ND
2017-03-02AD73051ND
2017-03-28AD771020.80 pCi/L
2017-03-28AD771014.96 pCi/L
2017-03-28AD771035.76 pCi/L
2017-03-28AD771002.75 pCi/L
2017-03-29AD773982.75 pCi/L
2017-03-29AD77397ND
2017-05-31AD86090ND
2017-07-06AD88431ND
2017-07-06AD88432ND
2017-07-06AD884332.75 pCi/L
2017-07-25AD90492ND
2017-07-26AD90761ND
2017-09-11AD95409ND
2017-09-11AD954080.74 pCi/L
2017-09-11AD954101.47 pCi/L
2017-09-26AD97971ND
2017-09-26AD9797011.32 pCi/L
2017-09-26AD979731.81 pCi/L
2017-09-26AD97972ND
2017-11-07AE038052.75 pCi/L
2017-11-07AE038061.61 pCi/L
2017-11-07AE03804ND
2017-11-07AE038072.48 pCi/L
2017-12-04AE06526ND