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EWG's Tap Water Database — 2021 UPDATE

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Nitrite

City of Houston

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.

MORE ABOUT THIS CONTAMINANT

 

42

Samples

0

Samples exceeding legal limit (MCL)

0

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
2013N/A00N/A
2014ND90ND
20150.000357 ppm281ND - 0.01000 ppm
2016N/A00N/A
2017ND10ND
2018N/A00N/A
2019ND40ND

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
2014-04-16AC50720ND
2014-08-14AC63582ND
2014-10-09AC69306ND
2014-10-09AC69305ND
2014-12-09AC74087ND
2014-12-09AC74086ND
2014-12-09AC74088ND
2014-12-18AC75396ND
2014-12-18AC75397ND
2015-03-04AC82759ND
2015-03-05AC82769ND
2015-03-24AC85778ND
2015-06-04AC94539ND
2015-06-04AC94540ND
2015-07-21AD00267ND
2015-07-21AD00268ND
2015-07-22AD00531ND
2015-07-22AD00532ND
2015-07-22AD00533ND
2015-07-22AD00530ND
2015-10-22AD11388ND
2015-10-22AD11384ND
2015-10-22AD11387ND
2015-10-22AD11382ND
2015-10-22AD11383ND
2015-10-22AD11385ND
2015-10-22AD113810.01000 ppm
2015-10-22AD11386ND
2015-11-12AD13272ND
2015-11-12AD13270ND
2015-11-12AD13269ND
2015-11-12AD13268ND
2015-11-12AD13274ND
2015-11-12AD13271ND
2015-11-12AD13273ND
2015-11-12AD13275ND
2015-12-08AD15859ND
2017-01-26AD66977ND
2019-01-16AE49959ND
2019-06-25AE71856ND
2019-11-18AE89369ND
2019-12-02AE90763ND