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National Drinking Water Database

Nitrate & nitrite in Washington

Nitrate and nitrite enter water from fertilizer runoff, leaching from septic tanks, and erosion of natural deposits.

The Most Polluted Communities in Washington

1,558 water utilities reported detecting Nitrate & nitrite in tap water since 2004, according to EWG's analysis of water quality data supplied by state water agencies

Ranked by highest average Nitrate & nitrite level

RankSystem Population Served Positive test results of total reported tests Average Level
1Clarktown Water System
Pasco, WA
8112 of 1223.33 ppm
(22.5 to 24.6 ppm)
2Columbia View Water System
Burbank, WA
35012 of 1221.84 ppm
(7.7 to 28.3 ppm)
3Beneficial Water
Pasco, WA
8412 of 1221.66 ppm
(20.5 to 22.3 ppm)
4Pathfinder Mobile Home Park
Kennewick, WA
7312 of 1217.15 ppm
(12.5 to 21.2 ppm)
5Northwood Park System
Lynden, WA
5012 of 1216.72 ppm
(9.6 to 20.7 ppm)
6Sun Harbor Water District #3
Burbank, WA
18713 of 1315.44 ppm
(4.53 to 18.2 ppm)
7Delta Water Association
Lynden, WA
42017 of 1715.25 ppm
(13.1 to 16.85 ppm)
8Rathbone Park Water Assoc
Ferndale, WA
24023 of 2314.51 ppm
(10.9 to 16.5 ppm)
9Northwood Water Association
Everson, WA
4913 of 1314.18 ppm
(11.5 to 16.7 ppm)
10Harrison-Ray-Burbank Water System
Pasco, WA
65612 of 1614.17 ppm
(0 to 29.2 ppm)

Health Based Limits for Nitrate & nitrite

Maximum Contaminant Limit (MCL)The enforceable standard which defines the highest level of a contaminant that is allowed in drinking water. MCLs are set as close to health-based limits (Maximum Contaminant Level Goals, or MCLGs) as feasible using the best available analytical and treatment technologies and taking cost into consideration. Source: U.S. Environmental Protection Agency.10 ppm
Maximum Contaminant Limit Goal (MCLG)A non-enforceable health goal that is set at a level at which no known or anticipated adverse effect on the health of persons occurs and which allows an adequate margin of safety. Source: U.S. Environmental Protection Agency.10 ppm
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.10 ppm

Violation Summary for Nitrate & nitrite in Washington

There are no violations reported for this contaminant in Washington