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EWG's Tap Water Database — 2019 UPDATE

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N-Nitrosodimethylamine (NDMA)

Los Angeles Department of Water and Power

N-Nitrosodimethylamine is one of the DNA-damaging, cancer-causing contaminants called N-nitrosamines that can form during water treatment with the use of certain disinfectants, such as chloramine. Read More.

Pollution of water sources with effluent from municipal wastewater treatment plants and runoff from animal feeding operations contributes to nitrosamine formation. Fifteen different nitrosamines are listed as carcinogens in the U.S. Department of Health and Human Services National Toxicology Program Report on Carcinogens. The federal government has not set a legal limit for nitrosamines in drinking water and water utilities typically do not test for these contaminants. California has set a public health goal for one of the most common nitrosamines, N-nitrosodimethylamine or NDMA, at 0.003 parts per billion in drinking water, a concentration that corresponds to an estimated one-in-one-million cancer risk.

Click here to read more about disinfection byproducts.

 

37

Samples

0

Samples exceeding legal limit (MCL)

0

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
2012N/A00N/A
2013N/A00N/A
2014ND50ND
2015ND100ND
2016ND50ND
2017ND170ND

ppt = parts per trillion

State and national drinking water standards and health guidelines

EWG Health Guideline 3 ppt

The EWG Health Guideline of 3 ppt for n-nitrosodimethylamine 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. This health guideline protects against cancer.

ppt = parts per trillion

All test results

Date Lab ID Result
2014-08-269590-159-0945ND
2014-09-299590-159-1050ND
2014-10-169590-159-1025ND
2014-11-119590-159-0905ND
2014-12-319590-159-1200ND
2015-01-269590-159-0950ND
2015-02-249590-159-0940ND
2015-05-079590-159-1105ND
2015-06-199590-159-0900ND
2015-07-169590-159-0950ND
2015-08-209590-159-1000ND
2015-09-289590-159-1000ND
2015-10-309590-159-1050ND
2015-11-279590-159-0930ND
2015-12-119590-159-0845ND
2016-01-139590-159-1040ND
2016-02-279590-159-0840ND
2016-03-299590-159-1000ND
2016-04-199590-159-0945ND
2016-11-299588-159-1005ND
2017-01-309590-159-1015ND
2017-02-169588-159-0940ND
2017-02-169588-159-0940ND
2017-03-109588-159-0920ND
2017-03-109588-159-0920ND
2017-06-229588-159-0830ND
2017-06-229588-159-0830ND
2017-07-109588-159-1135ND
2017-07-109588-159-1135ND
2017-08-299588-159-1215ND
2017-08-299588-159-1215ND
2017-09-279588-159-1030ND
2017-09-279588-159-1030ND
2017-10-209588-159-1000ND
2017-10-209588-159-1000ND
2017-11-039588-159-1050ND
2017-11-039588-159-1050ND