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.
| State | Water Suppliers with Nitrate & nitrite contamination | Water suppliers reporting Nitrate & nitrite above health-based limits | ||
|---|---|---|---|---|
| Systems | Population | Systems | Population | |
| California | 877 | 41,032,871 | 50 | 1,986,820 |
| Nebraska | 523 | 1,371,715 | 86 | 654,751 |
| Virginia | 98 | 953,409 | 78 | 284,824 |
| Wisconsin | 3,797 | 3,982,142 | 260 | 90,263 |
| New York | 489 | 3,817,181 | 3 | 55,669 |
| New Mexico | 511 | 1,496,230 | 4 | 38,385 |
| Washington | 1,558 | 3,995,467 | 47 | 21,308 |
| Illinois | 698 | 7,355,272 | 12 | 17,435 |
| North Carolina | 332 | 864,910 | 1 | 15,665 |
| Delaware | 126 | 838,019 | 7 | 7,512 |
| Wyoming | 137 | 236,111 | 2 | 6,089 |
| Idaho | 176 | 489,775 | 6 | 4,873 |
| Ohio | 575 | 6,411,826 | 6 | 3,456 |
| Texas | 5 | 43,582 | 2 | 3,116 |
| Nevada | 151 | 2,353,208 | 1 | 2,853 |
| Oregon | 254 | 1,830,519 | 2 | 2,040 |
| Arkansas | 266 | 1,828,391 | 1 | 1,017 |
| Montana | 576 | 640,878 | 6 | 888 |
| Maine | 310 | 621,640 | 1 | 768 |
| Alaska | 136 | 367,515 | 1 | 184 |
| New Jersey | 161 | 5,195,515 | 1 | 105 |
| North Dakota | 176 | 458,108 | 1 | 91 |
| Indiana | 163 | 2,803,327 | 1 | 76 |
| Utah | 203 | 2,920,147 | 1 | 48 |
| Connecticut | 526 | 2,578,649 | 1 | 36 |
| Missouri | 672 | 3,724,399 | 0 | 0 |
| Alabama | 202 | 3,564,747 | 0 | 0 |
| Kentucky | 78 | 2,333,055 | 0 | 0 |
| Iowa | 90 | 471,630 | 0 | 0 |
| Oklahoma | 1 | 471,000 | 0 | 0 |
| Florida | 10 | 427,309 | 0 | 0 |
| Rhode Island | 9 | 55,026 | 0 | 0 |
| Vermont | 49 | 53,437 | 0 | 0 |
| Colorado | 1 | 29,500 | 0 | 0 |
| Arizona | 2 | 11,133 | 0 | 0 |
| Total | 13,938 | 105,627,643 | 581 | 3,198,272 |
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
| Rank | System | Population Served | Positive test results of total reported tests | Average Level (Range) |
|---|---|---|---|---|
| 1 | Keswick Estates Keswick, VA | 120 | 1 of 1 | 30 ppm (30 ppm) |
| 2 | Town of Altavista Altavista, VA | 3,850 | 1 of 1 | 26.67 ppm (26.67 ppm) |
| 3 | Stoney Creek Sanitary District Woodstock, VA | 2,280 | 3 of 3 | 25 ppm (17.5 to 30 ppm) |
| 4 | Tony Morris / Morris Dairy Modesto, CA | 24 | 12 of 12 | 23.57 ppm (17.74 to 28.39 ppm) |
| 5 | Clarktown Water System Pasco, WA | 81 | 12 of 12 | 23.33 ppm (22.5 to 24.6 ppm) |
| 6 | Columbia View Water System Burbank, WA | 350 | 12 of 12 | 21.84 ppm (7.7 to 28.3 ppm) |
| 7 | Beneficial Water Pasco, WA | 84 | 12 of 12 | 21.66 ppm (20.5 to 22.3 ppm) |
| 8 | Courtney Subdivision Warwick, VA | 187 | 2 of 3 | 20 ppm (0 to 30 ppm) |
| 9 | Tree Acres Golf Course- Clubhouse Plover, WI | 50 | 5 of 5 | 19.76 ppm (18 to 20.9 ppm) |
| 10 | Coffee Creek Water Company Coffee Creek, MT | 35 | 13 of 13 | 19.37 ppm (15.1 to 24.1 ppm) |
Health Based Limits for Nitrate & nitrite
| Standard | Description | Level |
|---|---|---|
| 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 Goals | Defined 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 Violations | 661 |
| Monitoring Violations | 737 |
| Reporting Violations | 0 |