Know Your Environment. Protect Your Health.

Nitrate

City of Olympia

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.

 

31

Samples

0

Samples exceeding legal limit (MCL)

22

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
20180.790 ppm64ND - 2.41 ppm
20190.897 ppm65ND - 2.55 ppm
2020N/A00N/A
20210.845 ppm64ND - 2.58 ppm
20221.05 ppm76ND - 2.57 ppm
20230.920 ppm64ND - 2.82 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 Lab ID Result
2018-07-120.980 ppm
2018-07-12ND
2018-07-122.41 ppm
2018-07-12ND
2018-07-120.370 ppm
2018-07-120.980 ppm
2019-07-230.450 ppm
2019-07-230.110 ppm
2019-07-23ND
2019-07-232.55 ppm
2019-07-231.12 ppm
2019-07-231.15 ppm
2021-07-2041508591.02 ppm
2021-07-2041508611.02 ppm
2021-07-204150857ND
2021-07-204150860ND
2021-07-2041508582.58 ppm
2021-07-2041420060.450 ppm
2022-08-0243233010.440 ppm
2022-08-024323275ND
2022-10-1143685661.17 ppm
2022-10-1143685680.820 ppm
2022-10-1143603091.17 ppm
2022-10-1143603082.57 ppm
2022-11-2943845361.17 ppm
2023-07-254482573ND
2023-07-2544825681.14 ppm
2023-07-2544825702.82 ppm
2023-07-2544825670.410 ppm
2023-07-2544825721.15 ppm
2023-07-254482571ND