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EWG's Tap Water Database — 2021 UPDATE

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N-Nitrosodimethylamine (NDMA)

Central Basin Municipal Water District

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

 

79

Samples

0

Samples exceeding legal limit (MCL)

0

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
2014ND120ND
2015ND120ND
2016ND120ND
2017ND120ND
20180.133 ppt151ND - 2.00 ppt
2019ND160ND

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
2014-03-119588-033-1100ND
2014-03-119588-002-1130ND
2014-03-119588-001-1230ND
2014-06-109588-033-1000ND
2014-06-109588-002-1030ND
2014-06-109588-001-1100ND
2014-09-179588-033-0900ND
2014-09-179588-002-0930ND
2014-09-179588-001-1030ND
2014-12-179588-033-0900ND
2014-12-179588-002-1000ND
2014-12-179588-001-1100ND
2015-03-109588-002-0900ND
2015-03-109588-033-0800ND
2015-03-109588-001-1330ND
2015-06-249588-033-0930ND
2015-06-249588-002-1000ND
2015-06-249588-001-1200ND
2015-09-169588-033-1000ND
2015-09-169588-001-1100ND
2015-09-169588-002-1245ND
2015-12-029588-001-1230ND
2015-12-029588-033-0900ND
2015-12-029588-002-1030ND
2016-03-089588-001-1145ND
2016-03-089588-033-1115ND
2016-03-089588-002-1210ND
2016-06-069588-001-1105ND
2016-06-069588-033-0818ND
2016-06-069588-002-0901ND
2016-09-209588-001-1125ND
2016-09-209588-002-1015ND
2016-09-209588-033-1000ND
2016-12-069588-033-0830ND
2016-12-069588-001-1010ND
2016-12-069588-002-0900ND
2017-03-139588-002-1250ND
2017-03-139588-001-1050ND
2017-03-139588-033-0945ND
2017-06-069588-002-1000ND
2017-06-069588-001-0845ND
2017-06-069588-033-0730ND
2017-09-189588-033-0822ND
2017-09-189588-001-1132ND
2017-09-189588-002-1237ND
2017-12-059588-033-0805ND
2017-12-059588-002-1020ND
2017-12-059588-001-0850ND
2018-03-199588-033-08152.00 ppt
2018-03-199588-002-0900ND
2018-03-199588-001-0845ND
2018-06-139588-002-1005ND
2018-06-139588-001-1020ND
2018-07-109588-033-0900ND
2018-09-189588-001-1130ND
2018-09-189588-002-1145ND
2018-09-249588-001-1308ND
2018-09-249588-033-0838ND
2018-09-249588-002-0849ND
2018-12-119588-002-0838ND
2018-12-119588-001-0910ND
2018-12-199588-002-1045ND
2018-12-199588-001-1035ND
2019-03-189588-002-0800ND
2019-03-189588-001-0810ND
2019-03-219588-001-0950ND
2019-03-219588-002-1000ND
2019-06-059588-002-1000ND
2019-06-059588-001-0915ND
2019-06-119588-002-0940ND
2019-06-119588-001-0935ND
2019-09-119588-002-0820ND
2019-09-119588-001-0841ND
2019-09-249588-002-1120ND
2019-09-249588-001-1110ND
2019-12-059588-002-0900ND
2019-12-059588-001-0930ND
2019-12-189588-002-0910ND
2019-12-189588-001-0905ND