Nitrate and nitrite
Oklahoma University
Nitrate and nitrite enter water from fertilizer runoff, septic tanks and urban runoff. These contaminants can cause oxygen deprivation for infants and increase the risk of cancer. Nitrite is significantly more toxic than nitrate. Click here to read more about nitrate.
Testing results - average by year
Year | Average result | Samples taken | Detections | Range of results |
---|---|---|---|---|
2014 | 0.262 ppm | 31 | 22 | ND - 0.658 ppm |
2015 | 0.116 ppm | 31 | 9 | ND - 0.775 ppm |
2016 | 0.439 ppm | 31 | 21 | ND - 1.47 ppm |
2017 | 0.556 ppm | 38 | 34 | ND - 2.28 ppm |
2018 | 0.354 ppm | 27 | 24 | ND - 0.758 ppm |
2019 | 0.399 ppm | 28 | 27 | ND - 0.721 ppm |
ppm = parts per million
State and national drinking water standards and health guidelines
EWG Health Guideline 0.14 ppm
The health guideline of 0.14 parts per million, or ppm, for nitrate and nitrite is based on the equivalent health guideline for nitrate, as defined in a peer-reviewed scientific study by EWG. This guideline represents a one-in-one-million annual cancer risk level.
EPA Maximum Contaminant
Level (MCL) 10 ppm
ppm = parts per million
All test results
Date | Lab ID | Result |
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