Know Your Environment. Protect Your Health.

Nitrate and nitrite

City of Tacoma

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.

 

29

Samples

0

Samples exceeding legal limit (MCL)

21

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
20182.08 ppm119ND - 4.60 ppm
2019ND10ND
2020N/A00N/A
20212.22 ppm64ND - 4.71 ppm
20222.88 ppm87ND - 3.55 ppm
20232.16 ppm32ND - 4.06 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

ppm = parts per million

All test results

Date Lab ID Result
2018-02-072.40 ppm
2018-03-124.20 ppm
2018-03-194.60 ppm
2018-04-11ND
2018-04-11ND
2018-06-122.30 ppm
2018-06-122.80 ppm
2018-06-212.00 ppm
2018-06-212.10 ppm
2018-07-192.40 ppm
2018-10-180.0380 ppm
2019-12-05ND
2021-06-2141363002.68 ppm
2021-06-2141362962.65 ppm
2021-06-2141362973.29 ppm
2021-06-2141362984.71 ppm
2021-06-304143413ND
2021-07-214159325ND
2022-09-1543711972.53 ppm
2022-10-114371889ND
2022-11-1543845332.77 ppm
2022-12-2744006883.55 ppm
2022-12-2744006883.55 ppm
2022-12-2744006883.55 ppm
2022-12-2744006883.55 ppm
2022-12-2744006883.55 ppm
2023-07-1244996874.06 ppm
2023-07-1244996892.43 ppm
2023-10-204549137ND