Menu

EWG's Tap Water Database — 2019 UPDATE

Donate

Nitrate and nitrite

City of Houston

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.

 

92

Samples

0

Samples exceeding legal limit (MCL)

38

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
20120.107 ppm3023ND - 0.300 ppm
20130.131 ppm2519ND - 0.340 ppm
20140.0678 ppm95ND - 0.270 ppm
20150.107 ppm2821ND - 0.350 ppm
2016N/A00N/A
2017N/A00N/A

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
2012-04-10AB863700.0300 ppm
2012-04-10AB863660.01000 ppm
2012-04-10AB863690.270 ppm
2012-04-10AB863680.01000 ppm
2012-05-23AB90553ND
2012-05-23AB90561ND
2012-05-23AB905600.130 ppm
2012-05-23AB90552ND
2012-05-23AB90546ND
2012-05-23AB90566ND
2012-05-23AB905620.170 ppm
2012-06-12AB922620.0800 ppm
2012-06-12AB922660.150 ppm
2012-06-12AB92265ND
2012-06-12AB922630.0200 ppm
2012-06-12AB922610.240 ppm
2012-07-24AB960260.300 ppm
2012-07-24AB960210.180 ppm
2012-07-24AB960180.190 ppm
2012-07-24AB960170.0300 ppm
2012-07-24AB960190.0200 ppm
2012-07-24AB960160.280 ppm
2012-07-24AB960200.160 ppm
2012-11-19AC053740.160 ppm
2012-11-19AC053790.150 ppm
2012-11-19AC053780.220 ppm
2012-11-19AC053750.280 ppm
2012-11-19AC05376ND
2012-11-19AC053730.01000 ppm
2012-11-19AC053770.130 ppm
2013-02-26AC114940.0300 ppm
2013-09-25AC312380.170 ppm
2013-09-25AC312360.140 ppm
2013-10-24AC33156ND
2013-10-24AC33158ND
2013-10-24AC33155ND
2013-10-24AC331570.140 ppm
2013-10-29AC335540.150 ppm
2013-10-29AC335530.180 ppm
2013-10-29AC33552ND
2013-10-29AC335560.190 ppm
2013-10-29AC33557ND
2013-10-29AC335610.0400 ppm
2013-10-29AC33555ND
2013-10-29AC335580.240 ppm
2013-10-29AC335510.0600 ppm
2013-11-04AC339310.310 ppm
2013-11-04AC339280.280 ppm
2013-11-04AC339260.250 ppm
2013-11-04AC339300.220 ppm
2013-11-04AC339250.340 ppm
2013-11-04AC339290.190 ppm
2013-11-04AC339320.320 ppm
2013-11-04AC339360.01000 ppm
2013-11-04AC339270.01000 ppm
2014-04-16AC50720ND
2014-08-14AC635820.160 ppm
2014-10-09AC693060.01000 ppm
2014-10-09AC69305ND
2014-12-09AC74088ND
2014-12-09AC740860.150 ppm
2014-12-09AC740870.270 ppm
2014-12-18AC753960.0200 ppm
2014-12-18AC75397ND
2015-03-04AC827590.01000 ppm
2015-03-05AC827690.0300 ppm
2015-03-24AC857780.310 ppm
2015-06-04AC945390.01000 ppm
2015-06-04AC945400.160 ppm
2015-07-21AD00267ND
2015-07-21AD00268ND
2015-07-22AD005330.01000 ppm
2015-07-22AD005320.01000 ppm
2015-07-22AD005310.240 ppm
2015-07-22AD005300.0700 ppm
2015-10-22AD113810.01000 ppm
2015-10-22AD113860.190 ppm
2015-10-22AD11385ND
2015-10-22AD113830.0600 ppm
2015-10-22AD113820.130 ppm
2015-10-22AD11387ND
2015-10-22AD11384ND
2015-10-22AD11388ND
2015-11-12AD132700.350 ppm
2015-11-12AD132690.110 ppm
2015-11-12AD132680.240 ppm
2015-11-12AD132740.270 ppm
2015-11-12AD132720.220 ppm
2015-11-12AD132730.270 ppm
2015-11-12AD132750.160 ppm
2015-11-12AD13271ND
2015-12-08AD158590.130 ppm