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National Drinking Water Database


National Drinking Water Database - Chemical Contaminants

Nitrate & nitrite


Status: Regulated - EPA has established a maximum legal limit in tapwater for this contaminant.

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

 
Detected
Found above
health guidelines
Found above
legal limit
States
35
25
25
Water utilities
13,938
581
581
People Served
105,627,643
3,198,272
3,198,272

Nitrate & nitrite Exposure by State

Water utilities in 35 states have reported detecting Nitrate & nitrite in treated tap water since 2004, according to EWG's analysis of water quality data supplied by state water agencies.

StateWater Suppliers with Nitrate & nitrite contaminationWater suppliers reporting Nitrate & nitrite above health-based limits
SystemsPopulationSystemsPopulation
California87741,032,871501,986,820
Nebraska5231,371,71586654,751
Virginia98953,40978284,824
Wisconsin3,7973,982,14226090,263
New York4893,817,181355,669
New Mexico5111,496,230438,385
Washington1,5583,995,4674721,308
Illinois6987,355,2721217,435
North Carolina332864,910115,665
Delaware126838,01977,512
Wyoming137236,11126,089
Idaho176489,77564,873
Ohio5756,411,82663,456
Texas543,58223,116
Nevada1512,353,20812,853
Oregon2541,830,51922,040
Arkansas2661,828,39111,017
Montana576640,8786888
Maine310621,6401768
Alaska136367,5151184
New Jersey1615,195,5151105
North Dakota176458,108191
Indiana1632,803,327176
Utah2032,920,147148
Connecticut5262,578,649136
Missouri6723,724,39900
Alabama2023,564,74700
Kentucky782,333,05500
Iowa90471,63000
Oklahoma1471,00000
Florida10427,30900
Rhode Island955,02600
Vermont4953,43700
Colorado129,50000
Arizona211,13300
Total13,938105,627,6435813,198,272

The Most Polluted Communities

13,938 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
(Range)
1Keswick Estates
Keswick, VA
1201 of 130 ppm
(30 ppm)
2Town of Altavista
Altavista, VA
3,8501 of 126.67 ppm
(26.67 ppm)
3Stoney Creek Sanitary District
Woodstock, VA
2,2803 of 325 ppm
(17.5 to 30 ppm)
4Tony Morris / Morris Dairy
Modesto, CA
2412 of 1223.57 ppm
(17.74 to 28.39 ppm)
5Clarktown Water System
Pasco, WA
8112 of 1223.33 ppm
(22.5 to 24.6 ppm)
6Columbia View Water System
Burbank, WA
35012 of 1221.84 ppm
(7.7 to 28.3 ppm)
7Beneficial Water
Pasco, WA
8412 of 1221.66 ppm
(20.5 to 22.3 ppm)
8Courtney Subdivision
Warwick, VA
1872 of 320 ppm
(0 to 30 ppm)
9Tree Acres Golf Course- Clubhouse
Plover, WI
505 of 519.76 ppm
(18 to 20.9 ppm)
10Coffee Creek Water Company
Coffee Creek, MT
3513 of 1319.37 ppm
(15.1 to 24.1 ppm)

Health Based Limits for Nitrate & nitrite

StandardDescriptionLevel
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

Testing Summary for Nitrate & nitrite

Are tests routinely required for Nitrate & nitrite by federal law?Yes
Water suppliers reporting tests for Nitrate & nitrite (2004-2009):21,805 of 47,576
Average testing rate for water supplier reporting tests (2004-2009):0.8 per year

Violation Summary for Nitrate & nitrite

Data from the U.S. Environmental Protection Agency includes the following violations of federal standards for Nitrate & nitrite since 2004

Maximum Contaminant Level Exceedance Violations661
Monitoring Violations737
Reporting Violations0