EWG's Tap Water Database — 2019 UPDATE


Nitrate and nitrite

Boone-florence Water Commission

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
20120.760 ppm220.570 ppm - 0.950 ppm
20130.795 ppm12120.480 ppm - 1.03 ppm
20140.992 ppm990.700 ppm - 1.43 ppm
20150.875 ppm220.850 ppm - 0.900 ppm
20160.821 ppm880.530 ppm - 1.51 ppm
20170.965 ppm11110.550 ppm - 1.39 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