Know Your Environment. Protect Your Health.

Nitrate and nitrite

Redmond Water Department

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.

 

5

Samples

0

Samples exceeding legal limit (MCL)

5

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
2018N/A00N/A
2019N/A00N/A
2020N/A00N/A
20210.540 ppm110.540 ppm
20220.365 ppm220.200 ppm - 0.530 ppm
20230.395 ppm220.310 ppm - 0.480 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
2021-05-1121322640.540 ppm
2022-08-1022-514720.200 ppm
2022-08-1022-514750.530 ppm
2023-07-1323-408820.310 ppm
2023-07-1323-408870.480 ppm