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EWG's Tap Water Database — 2019 UPDATE

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Nitrate and nitrite

San Francisco Regional Water System

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.

 

14

Samples

0

Samples exceeding legal limit (MCL)

0

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
2012ND30ND
2013ND10ND
2014ND30ND
2015ND30ND
2016ND10ND
2017ND30ND

ppm = parts per million

State and national drinking water standards and health guidelines

EWG Health Guideline 0.14 ppm

The 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
2012-06-139553-001-1045ND
2012-06-139553-015-1220ND
2012-07-249553-016-0915ND
2013-06-189590-001-1110ND
2014-06-179553-001-1130ND
2014-06-179553-016-0904ND
2014-09-169553-015-1035ND
2015-05-279553-016-0830ND
2015-05-279553-001-1235ND
2015-06-189553-015-0915ND
2016-06-219590-016-1055ND
2017-06-199590-016-0953ND
2017-06-199590-015-1100ND
2017-06-199590-001-1025ND