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National Drinking Water Database


Nitrate in Oregon


Nitrate enters drinking water sources from fertilizer runoff, leaching septic tanks, and erosion of natural deposits; it is also emitted by chemical, petrochemical and metal-finishing industries. [read more]

The Most Polluted Communities in Oregon

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

Ranked by highest average Nitrate level

RankSystem Population Served Positive test results of total reported tests Average Level
(Range)
1Westland Estates Water System
Hermiston, OR
6014 of 1410.75 ppm
(7 to 15 ppm)
2City of Irrigon
Irrigon, OR
1,74048 of 538.52 ppm
(0 to 15 ppm)
3Sunridge Water Inc
Vancouver, OR
10011 of 118.29 ppm
(6.74 to 14 ppm)
4Odell Water Company
Odell, OR
35516 of 167.85 ppm
(6 to 10 ppm)
5Harwoods Mobile Manor
Junction City, OR
707 of 77.76 ppm
(6.2 to 8.9 ppm)
6Hat Rock Water Company
Hermiston, OR
807 of 76.99 ppm
(4.7 to 9 ppm)
7Island City
Island City, OR
9809 of 96.74 ppm
(3.5 to 12.6 ppm)
8Coburg/Pioneer Valley Estates
Coburg, OR
1259 of 96.7 ppm
(5.5 to 8 ppm)
9City of Monmouth
Monmouth, OR
8,11035 of 356.44 ppm
(1.2 to 10.95 ppm)
10Country Garden Estates Mhp
Irrigon, OR
853 of 36.16 ppm
(5.79 to 6.73 ppm)

Health Based Limits for Nitrate

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
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.10 ppm
Children's health-based limit for 1-day exposureConcentration of a chemical in drinking water that is not expected to cause any adverse, noncarcinogenic health effects for up to one day of exposure. The One-Day health-based limit (or Health Advisory, HA) is typically set to protect a 10-kg child consuming 1 liter of water per day. Source: U.S. Environmental Protection Agency.10 ppm
Children's health-based limit for 10-day exposureConcentration of a chemical in drinking water that is not expected to cause any adverse, noncarcinogenic effects for up to ten days of exposure. The Ten-Day health-based limit (or Health Advisory, HA) is typically set to protect a 10-kg child consuming 1 liter of water per day. Source: U.S. Environmental Protection Agency.10 ppm

Violation Summary for Nitrate in Oregon

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

Violation TypeNumber of Violations
Failure to monitor regularly422
Over maximum contaminant level, Single Sample6
Over maximum contaminant level, Average3