Know Your Environment. Protect Your Health.

Nitrate and nitrite

Arlington 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.

 

11

Samples

0

Samples exceeding legal limit (MCL)

5

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
20180.330 ppm330.140 ppm - 0.710 ppm
20190.900 ppm220.140 ppm - 1.66 ppm
2020N/A00N/A
20210.785 ppm220.110 ppm - 1.46 ppm
20220.655 ppm220.110 ppm - 1.20 ppm
20230.500 ppm21ND - 1.000 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
2018-04-170.710 ppm
2018-08-140.140 ppm
2018-08-140.140 ppm
2019-04-021.66 ppm
2019-09-110.140 ppm
2021-04-0640958861.46 ppm
2021-09-1541807770.110 ppm
2022-04-1342688991.20 ppm
2022-09-1443596780.110 ppm
2023-04-0444397561.000 ppm
2023-09-214527327ND