EWG's Tap Water Database — 2019 UPDATE


Nitrate and nitrite

Town of Gilbert

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.





Samples exceeding legal limit (MCL)


Samples exceeding
health guidelines

Testing results - average by year

YearAverage resultSamples takenDetectionsRange of results
20123.39 ppm4239ND - 7.40 ppm
20132.61 ppm1715ND - 6.30 ppm
20144.00 ppm21ND - 8.00 ppm
20156.30 ppm226.20 ppm - 6.40 ppm
20163.26 ppm880.710 ppm - 6.30 ppm

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
2012-01-09PVA0476-013.40 ppm
2012-01-09PVA0475-01I0.280 ppm
2012-01-12PVA0815-016.40 ppm
2012-01-12PVA0814-014.80 ppm
2012-01-17PVA1028-015.80 ppm
2012-01-18PVA1137-011.70 ppm
2012-01-19PVA1240-013.30 ppm
2012-01-25PVA1556-011.80 ppm
2012-02-13PVB0899-011.90 ppm
2012-02-13PVB0897-011.70 ppm
2012-02-13PVB0898-010.810 ppm
2012-02-28PVB1867-01B0.860 ppm
2012-03-01PVC0073-01B0.230 ppm
2012-03-15PVC1257-01I7.30 ppm
2012-03-27PVC1957-014.20 ppm
2012-04-02PVD0064-010.450 ppm
2012-04-03PVD0160-015.00 ppm
2012-04-03PVD0158-016.20 ppm
2012-04-09PVD0612-013.70 ppm
2012-04-09PVD0611-01I0.980 ppm
2012-04-23PVD1652-013.00 ppm
2012-05-01PVE0080-015.50 ppm
2012-05-02PVE0219-01I7.40 ppm
2012-07-02PVG0060-014.90 ppm
2012-07-02PVG0059-016.10 ppm
2012-07-02PVG0068-01B1.80 ppm
2012-07-09PVG0476-014.30 ppm
2012-07-24PVG1658-017.20 ppm
2012-07-26PVG1876-017.20 ppm
2012-08-01PVH0103-013.00 ppm
2012-08-28PVH2122-010.680 ppm
2012-08-28PVH2120-012.70 ppm
2012-09-04PVI0086-012.90 ppm
2012-10-01PVJ0070-01I6.50 ppm
2012-10-01PVJ0063-016.10 ppm
2012-10-09PVJ0683-014.30 ppm
2012-10-24PVJ1673-012.50 ppm
2012-12-05PVL0292-015.00 ppm
2012-12-20PVL1426-01I0.310 ppm
2013-01-16PWA1110-012.00 ppm
2013-01-17PWA1114-013.60 ppm
2013-01-28PWA1663-013.20 ppm
2013-07-29550-7636-11.70 ppm
2013-07-29550-7634-1I3.00 ppm
2013-07-30550-7716-1I0.710 ppm
2013-07-31550-7815-1I6.30 ppm
2013-07-31550-7810-1I2.10 ppm
2013-08-07550-8302-13.50 ppm
2013-08-12550-8579-14.30 ppm
2013-08-13550-8672-11.70 ppm
2013-08-27550-9504-1I2.60 ppm
2013-08-29550-9668-1I3.90 ppm
2013-10-15201310150527I3.40 ppm
2013-10-22201310220364I2.40 ppm
2014-12-02201412090218I8.00 ppm
2015-01-28201501280356I6.20 ppm
2015-08-17201508170182I6.40 ppm
2016-01-19201601190321I1.70 ppm
2016-01-26201601260298I0.710 ppm
2016-02-08201602080053I5.50 ppm
2016-02-08201602080042I2.10 ppm
2016-03-02201603020441I3.30 ppm
2016-04-07201604070686I6.30 ppm
2016-04-19201604190185I3.60 ppm
2016-05-31201605310460I2.90 ppm