Know Your Environment. Protect Your Health.

Nitrate and nitrite

Nob Hill Water Association

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.

 

20

Samples

0

Samples exceeding legal limit (MCL)

12

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
20180.374 ppm54ND - 0.900 ppm
20190.292 ppm54ND - 0.560 ppm
2020N/A00N/A
20210.246 ppm54ND - 0.510 ppm
20220.543 ppm53ND - 1.80 ppm
2023N/A00N/A

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
2018-07-310.330 ppm
2018-07-310.120 ppm
2018-07-31ND
2018-07-310.520 ppm
2018-07-310.900 ppm
2019-07-020.440 ppm
2019-07-020.560 ppm
2019-07-020.0900 ppm
2019-07-02ND
2019-07-020.370 ppm
2021-07-0741332800.0800 ppm
2021-07-0741332810.300 ppm
2021-07-074133279ND
2021-07-0741332770.340 ppm
2021-07-0741332780.510 ppm
2022-03-2143089530.514 ppm
2022-07-064305228ND
2022-07-064305229ND
2022-07-0643052270.400 ppm
2022-07-0643052301.80 ppm