Know Your Environment. Protect Your Health.

Nitrate and nitrite

City of Redmond Water System

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.

 

17

Samples

0

Samples exceeding legal limit (MCL)

10

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
20180.533 ppm31ND - 1.60 ppm
20190.395 ppm42ND - 0.970 ppm
2020N/A00N/A
20210.720 ppm43ND - 1.30 ppm
20220.793 ppm32ND - 1.80 ppm
20230.603 ppm32ND - 1.10 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

ppm = parts per million

All test results

Date Lab ID Result
2018-05-021.60 ppm
2018-05-02ND
2018-05-02ND
2019-03-06ND
2019-03-06ND
2019-03-060.610 ppm
2019-03-060.970 ppm
2021-04-144099168ND
2021-04-1440991661.30 ppm
2021-04-1440991700.790 ppm
2021-09-0241807560.790 ppm
2022-04-274279549ND
2022-04-2742795501.80 ppm
2022-04-2742795480.580 ppm
2023-04-034434932ND
2023-04-0344349331.10 ppm
2023-04-0344349310.710 ppm