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N-Nitrosodimethylamine (NDMA)

Status: No national drinking water standard exists

 

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.

2015:

FOUND
FOUND ABOVE HEALTH GUIDELINES

2

states detected

46

utilities detected

3.9 million

people served

1

states over health guideline

11

utilities over health guideline

809,000

people served over health guideline

Health concerns for n-nitrosodimethylamine

Cancer

State and national drinking water standards and health guidelines

Health Guideline 3 ppt

The 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.

States reporting n-nitrosodimethylamine in drinking water

UTILITIES REPORTING ABOVE HEALTH GUIDELINES UTILITIES WITH CONTAMINATION
State UtilitiesPeople Served UtilitiesPeople Served
California11809,042411,948,702
Virginia0021,269,000
District Of Columbia003644,822
MORE
LESS

Utilities with the highest amounts of n-nitrosodimethylamine, 2015

ALL UTILITIES
LARGE UTILITIES
UtilityLocationTestsAverage levelPeople served
San Gabriel Valley Water Company- El Monte*El Monte, CA101 of 23018.5 ppt226,904
California Water Service Company - East Los AngelesSan Jose, CA5 of 65.80 ppt150,446
California Water Service Company - DominguezSan Jose, CA2 of 24.70 ppt142,111
California Water Service Company - Palos VerdeSan Jose, CA6 of 64.35 ppt69,883
California Water Service - LivermoreLivermore, CA2 of 33.60 ppt56,700
Valencia Water Company*Valencia, CA2 of 23.50 ppt117,251
California Water Service Company - Hermosa / Redondo BeachSan Jose, CA6 of 82.64 ppt95,605
California Domestic Water Company*Whittier, CA24 of 1151.90 ppt1,200
Zone 7 Water Agency*Livermore, CA2 of 41.73 ppt40
Calleguas Municipal Water District*Thousand Oaks, CA1 of 21.05 ppt0
Washington Aqueduct Division*Washington, DC2 of 80.675 ppt0
Suburban Water Systems - San JoseCovina, CA2 of 290.138 ppt162,031
Monterey Park Water DepartmentMonterey Park, CA1 of 370.0540 ppt62,183

* This water utility supplies finished drinking water to at least one other water utility. The purchasing utility is not required to test for or report N-Nitrosodimethylamine (NDMA), but it likely has the contaminant in its water supply.

UtilityLocationTestsAverage levelPeople served
San Gabriel Valley Water Company- El Monte*El Monte, CA101 of 23018.5 ppt226,904
California Water Service Company - East Los AngelesSan Jose, CA5 of 65.80 ppt150,446
California Water Service Company - DominguezSan Jose, CA2 of 24.70 ppt142,111
California Water Service Company - Palos VerdeSan Jose, CA6 of 64.35 ppt69,883
California Water Service - LivermoreLivermore, CA2 of 33.60 ppt56,700
Valencia Water Company*Valencia, CA2 of 23.50 ppt117,251
California Water Service Company - Hermosa / Redondo BeachSan Jose, CA6 of 82.64 ppt95,605
Suburban Water Systems - San JoseCovina, CA2 of 290.138 ppt162,031
Monterey Park Water DepartmentMonterey Park, CA1 of 370.0540 ppt62,183

* This water utility supplies finished drinking water to at least one other water utility. The purchasing utility is not required to test for or report N-Nitrosodimethylamine (NDMA), but it likely has the contaminant in its water supply.