The Power of Information

National Drinking Water Database

Nitrate & nitrite in Montana

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

The Most Polluted Communities in Montana

576 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
1Coffee Creek Water Company
Coffee Creek, MT
3513 of 1319.37 ppm
(15.1 to 24.1 ppm)
2King Ranch Colony
Lewistown, MT
5513 of 1316.39 ppm
(11.6 to 20.8 ppm)
3Rapelje Water Users Assn
Rapelje, MT
7011 of 1116 ppm
(13.45 to 19.5 ppm)
4Midway Colony
751 of 18.46 ppm
(8.46 ppm)
5Crystal Springs Water System
Billings, MT
32712 of 127.98 ppm
(4.63 to 11.4 ppm)
6River Grove Estates TR Ct
Laurel, MT
10018 of 187.19 ppm
(1.93 to 15 ppm)
7Mobile City Home Park NO 2
Helena, MT
3003 of 36.8 ppm
(6.7 to 7 ppm)
8Mobile City Home Park NO 1
Helena, MT
1003 of 36.75 ppm
(6.3 to 7.11 ppm)
9Meadowland Hoa
Kalispell, MT
1504 of 46.66 ppm
(6.11 to 7.37 ppm)
10Town of Denton
Denton, MT
30121 of 216.65 ppm
(0.29 to 22.53 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 Montana

Data from the U.S. Environmental Protection Agency includes the following violations of federal standards in Montana since 2004

Violation TypeNumber of Violations
Failure to monitor regularly209
Over maximum contaminant level, Single Sample64
Over maximum contaminant level, Average2