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EWG's Tap Water Database — 2021 UPDATE

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N-Nitrosodimethylamine (NDMA)

Woodland-davis Clean 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.

MORE ABOUT THIS CONTAMINANT

 

63

Samples

0

Samples exceeding legal limit (MCL)

1

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
2014N/A00N/A
2015N/A00N/A
20160.660 ppt101ND - 6.60 ppt
2017ND110ND
2018ND220ND
2019ND200ND

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
2016-05-249588-002-1055ND
2016-05-249588-002-1055ND
2016-07-159588-002-1027ND
2016-07-159588-002-1027ND
2016-08-199588-002-1315ND
2016-08-199588-002-13156.60 ppt
2016-10-149588-002-1200ND
2016-10-149588-002-1200ND
2016-12-149588-002-1112ND
2016-12-149588-002-1112ND
2017-04-129588-002-1045ND
2017-04-129588-002-1045ND
2017-05-109588-002-1115ND
2017-05-119588-002-1110ND
2017-05-119588-002-1110ND
2017-09-139588-002-1001ND
2017-09-139588-002-1001ND
2017-11-089588-002-1130ND
2017-11-089588-002-1130ND
2017-12-139588-002-1032ND
2017-12-139588-002-1032ND
2018-01-099588-002-1059ND
2018-01-099588-002-1059ND
2018-02-149588-002-1112ND
2018-02-149588-002-1112ND
2018-03-199588-002-1400ND
2018-03-199588-002-1400ND
2018-04-119588-002-1034ND
2018-04-119588-002-1034ND
2018-05-099588-002-1030ND
2018-05-099588-002-1030ND
2018-06-139588-002-1124ND
2018-06-139588-002-1124ND
2018-07-119588-002-1050ND
2018-07-119588-002-1050ND
2018-08-089588-002-1121ND
2018-08-089588-002-1121ND
2018-09-129588-002-1035ND
2018-09-129588-002-1035ND
2018-11-149588-002-1200ND
2018-11-149588-002-1200ND
2018-12-129588-002-1040ND
2018-12-129588-002-1040ND
2019-01-099588-002-1021ND
2019-01-099588-002-1021ND
2019-02-139588-002-1220ND
2019-02-139588-002-1220ND
2019-04-109588-002-1155ND
2019-04-109588-002-1155ND
2019-05-089588-002-1111ND
2019-05-089588-002-1111ND
2019-06-209588-002-0928ND
2019-06-209588-002-0928ND
2019-07-109588-002-1130ND
2019-07-109588-002-1130ND
2019-08-219588-002-1300ND
2019-08-219588-002-1300ND
2019-10-099588-002-1150ND
2019-10-099588-002-1150ND
2019-11-069588-002-1024ND
2019-11-069588-002-1024ND
2019-12-169588-002-0950ND
2019-12-169588-002-0950ND