Know Your Environment. Protect Your Health.

Nitrate

Colville Water Department

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.

 

15

Samples

0

Samples exceeding legal limit (MCL)

6

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
20180.193 ppm32ND - 0.470 ppm
20190.211 ppm31ND - 0.633 ppm
2020N/A00N/A
20210.215 ppm31ND - 0.646 ppm
20220.122 ppm31ND - 0.366 ppm
20230.169 ppm32ND - 0.273 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
2018-07-25ND
2018-07-250.110 ppm
2018-09-270.470 ppm
2019-07-29ND
2019-07-29ND
2019-09-230.633 ppm
2021-06-144134646ND
2021-06-144134645ND
2021-09-2741757360.646 ppm
2022-06-234297832ND
2022-06-234297833ND
2022-12-1243851290.366 ppm
2023-06-224480288ND
2023-06-2244802850.273 ppm
2023-06-2244802870.233 ppm