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EWG's Tap Water Database — 2019 UPDATE

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Nitrite

San Francisco Regional Water System

Nitrite, closely related to the fertilizer chemical nitrate, comes from urban runoff and from fertilizer applied to agricultural lands to pollute drinking water. Nitrite is significantly more toxic than nitrate. Excessive nitrite in water can cause oxygen deprivation in infants and increase the risk of cancer.

 

15

Samples

0

Samples exceeding legal limit (MCL)

0

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
2012ND30ND
2013ND20ND
2014ND30ND
2015ND30ND
2016ND10ND
2017ND30ND

ppm = parts per million

State and national drinking water standards and health guidelines

EPA Maximum Contaminant
Level (MCL) 1 ppm

The legal limit for nitrite, established in 1991, was based on the rate of conversion of ingested nitrate into nitrite in adults. This limit may not fully protect against the risk of cancer due to nitrite exposure.

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
2013-10-079590-015-1024ND
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