Know Your Environment. Protect Your Health.

Nitrate

Portland Water System

Nitrate, a fertilizer chemical, frequently contaminates drinking water due to agricultural and urban runoff, and discharges from municipal wastewater treatment plants and septic tanks. Excessive nitrate in water can cause oxygen deprivation in infants and increase the risk of cancer. Click here to read more about nitrate.

 

9

Samples

0

Samples exceeding legal limit (MCL)

9

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
20180.994 ppm110.994 ppm
20191.17 ppm111.17 ppm
20200.992 ppm110.992 ppm
20210.846 ppm110.846 ppm
20220.843 ppm220.843 ppm
20231.06 ppm331.06 ppm

ppm = parts per million

State, National, and Health Guidelines for Drinking Water

EWG Health Guideline: 0.14 ppm

The EWG 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

The legal limit for nitrate, established in 1962, was developed to protect infants from acute methemoglobinemia, a life-threatening disorder of oxygen transport in the body. This limit does not fully protect against the risk of cancer and harm to the developing fetus.

ppm = parts per million

All test results

Date Result
2018-03-140.994 ppm
2019-03-141.17 ppm
2020-03-120.992 ppm
2021-03-250.846 ppm
2022-03-100.843 ppm
2022-03-100.843 ppm
2023-02-091.06 ppm
2023-02-091.06 ppm
2023-02-091.06 ppm