Nitrate and nitrite

Aquarion Water Company of Connecticut - Stamford

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
2014	0.185 ppm	4	4	0.175 ppm - 0.199 ppm
2015	N/A	0	0	N/A
2016	0.620 ppm	4	4	0.115 ppm - 2.08 ppm
2017	0.606 ppm	5	5	0.0560 ppm - 2.47 ppm
2018	0.00900 ppm	2	2	0.00500 ppm - 0.0130 ppm
2019	0.213 ppm	2	2	0.206 ppm - 0.220 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
2014-01-07	201400283-NOX	0.199 ppm
2014-01-07	201400282-IOCR	0.186 ppm
2014-05-05	201406146-IOCR	0.175 ppm
2014-05-05	201406147-NOX	0.179 ppm
2016-01-11	201600503-IOCR	0.166 ppm
2016-01-11	201600501-IOCR	0.115 ppm
2016-01-11	201600500-NOX	0.118 ppm
2016-10-31	201615141-NOX	2.08 ppm
2017-01-17	201701121-IOCR	0.0560 ppm
2017-01-17	201701124-NOX	0.209 ppm
2017-03-01	201703108-NOX	2.47 ppm
2017-03-13	201703761-IOCR	0.0660 ppm
2017-03-13	201703762-NOX	0.227 ppm
2018-01-02	201800018-IOCR	0.00500 ppm
2018-01-02	201800021-NOX	0.0130 ppm
2019-01-07	201900231-IOCR	0.206 ppm
2019-01-07	201900234-NOX	0.220 ppm