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EWG's Tap Water Database — 2021 UPDATE

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N-Nitrosodimethylamine (NDMA)

Castaic Lake Water Agency

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.

 

38

Samples

0

Samples exceeding legal limit (MCL)

0

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
2014ND60ND
2015ND80ND
2016ND60ND
2017ND60ND
2018ND60ND
2019ND60ND

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
2014-07-309588-006-0930ND
2014-07-309588-006-0930ND
2014-07-309588-005-0830ND
2014-07-309588-005-0830ND
2014-11-219588-004-1155ND
2014-11-219588-004-1155ND
2015-01-149588-004-1220ND
2015-01-149588-004-1220ND
2015-07-239590-006-0940ND
2015-07-239590-004-0750ND
2015-07-239590-004-0750ND
2015-07-239590-006-0940ND
2015-07-239590-005-0840ND
2015-07-239590-005-0840ND
2016-07-209590-005-1115ND
2016-07-209590-004-1035ND
2016-07-209590-004-1035ND
2016-07-209590-006-1215ND
2016-07-209590-006-1215ND
2016-07-209590-005-1115ND
2017-07-269590-004-1140ND
2017-07-269590-005-1300ND
2017-07-269590-005-1300ND
2017-07-269590-006-1405ND
2017-07-269590-006-1405ND
2017-07-269590-004-1140ND
2018-07-259590-006-1350ND
2018-07-259590-004-1230ND
2018-07-259590-004-1230ND
2018-07-259590-006-1350ND
2018-07-259590-005-1310ND
2018-07-259590-005-1310ND
2019-07-319590-006-1125ND
2019-07-319590-006-1125ND
2019-07-319590-004-1000ND
2019-07-319590-004-1000ND
2019-07-319590-005-1040ND
2019-07-319590-005-1040ND