Nitrate and nitrite

Carroll County

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.

MORE ABOUT THIS CONTAMINANT

Samples

Samples exceeding legal limit (MCL)

Samples exceeding
health guidelines

Testing results - average by year

Year	Average result	Samples taken	Detections	Range of results
2013	N/A	0	0	N/A
2014	0.493 ppm	4	2	ND - 1.40 ppm
2015	0.563 ppm	4	2	ND - 1.60 ppm
2016	0.578 ppm	4	3	ND - 1.50 ppm
2017	0.633 ppm	4	3	ND - 1.70 ppm
2018	0.643 ppm	4	2	ND - 1.80 ppm
2019	0.840 ppm	4	3	ND - 1.90 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
2014-03-03	AI29075	1.40 ppm
2014-03-04	AI29370	0.570 ppm
2014-03-04	AI29369	ND
2014-03-04	AI29368	ND
2015-03-05	AI68452	0.650 ppm
2015-03-05	AI68451	ND
2015-03-05	AI68450	ND
2015-04-29	AI75842	1.60 ppm
2016-02-24	AJ07042	1.50 ppm
2016-02-24	AJ07045	0.560 ppm
2016-02-24	AJ07044	ND
2016-02-24	AJ07043	0.250 ppm
2017-02-17	AJ46921	ND
2017-02-17	AJ46919	0.620 ppm
2017-02-17	AJ46918	1.70 ppm
2017-02-21	AJ46920	0.210 ppm
2018-02-21	AJ84464	ND
2018-02-21	AJ84463	0.770 ppm
2018-02-21	AJ84462	ND
2018-02-21	AJ84461	1.80 ppm
2019-02-05	AK10890	ND
2019-02-05	AK10893	1.90 ppm
2019-02-05	AK10892	1.20 ppm
2019-02-05	AK10891	0.260 ppm