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National Drinking Water Database

n-Nitrosodimethylamine in California

n-Nitrosodimethylamine is a carcinogenic water contaminant released from various industrial processes; it also forms in drinking water as disinfection byproduct of chloramination and from agricultural runoff.

The Most Polluted Communities in California

20 water utilities reported detecting n-Nitrosodimethylamine in tap water since 2004, according to EWG's analysis of water quality data supplied by state water agencies

Ranked by highest average n-Nitrosodimethylamine level

RankSystem Population Served Positive test results of total reported tests Average Level
1San Gabriel Valley Water Co.-El Monte
El Monte, CA
153,657199 of 2110.04 ppb
(0 to 0.13 ppb)
2Pomona - City, Water Dept.
Pomona, CA
156,50067 of 860.02 ppb
(0 to 0.26 ppb)
3Santa FE I.D.
Rancho Santa Fe, CA
20,8283 of 30.01 ppb
(<0.01 to 0.01 ppb)
4Gswc-San Dimas
San Dimas, CA
52,0512 of 10< 0.01 ppb
(0 to 0.07 ppb)
5California Water Service Co. - Palos Ver
Rancho Palos Verdes, CA
68,76610 of 10< 0.01 ppb
(<0.01 to 0.01 ppb)
6Monrovia-City, Water Dept.
Monrovia, CA
40,0501 of 1< 0.01 ppb
(< .01 to 0.004 ppb)
7California Domestic Water Company
Whittier, CA
619144 of 199< 0.01 ppb
(0 to 0.03 ppb)
8Suburban Water Systems-Whittier
Covina, CA
58,08989 of 147< 0.01 ppb
(0 to 0.01 ppb)
9Three Valleys Mwd
Claremont, CA
01 of 2< 0.01 ppb
(< .01 to 0.004 ppb)
10Suburban Water Systems-San Jose
Covina, CA
110,602125 of 244< 0.01 ppb
(0 to 0.03 ppb)

Health Based Limits for n-Nitrosodimethylamine

EPA Human Health Water Quality CriteriaWater quality criteria set by the US EPA provide guidance for states and tribes authorized to establish water quality standards under the Clean Water Act (CWA) to protect human health. These are non-enforceable standards based upon exposure by both drinking water and the contribution of water contamination to other consumed foods. Source: U.S. Environmental Protection Agency.<0.01 ppb
Health-Based Screening LevelA benchmark concentration of contaminants in water that may be of potential concern for human health, if exceeded. For noncarcinogens, the HBSL represents the contaminant concentration in drinking water that is not expected to cause any adverse effects over a lifetime of exposure. For carcinogens, the HBSL range represents the contaminant concentration in drinking water that corresponds to an excess estimated lifetime cancer risk of 1 chance in 1 million to 1 chance in 10 thousand. Source: U.S. Geological Survey.<0.01 ppb-0.07 ppb
California Public Health GoalsDefined by the State of California Office of Environmental Health Hazard Assessment (OEHHA) as the level of contaminant that is allowed in drinking water. For acutely toxic substances, levels are set at which scientific evidence indicates that no known or anticipated adverse effects on health will occur, plus an adequate margin-of safety. PHGs for carcinogens or other substances which can cause chronic disease shall be based solely on health effects without regard to cost impacts and shall be set at levels which OEHHA has determined do not pose any significant risk to health.<0.01 ppb

Violation Summary for n-Nitrosodimethylamine in California

There are no violations reported for this contaminant in California