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EWG's Tap Water Database — 2021 UPDATE

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Nitrate and nitrite

Connecticut Water Company - Northern Region-Western System

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

 

91

Samples

0

Samples exceeding legal limit (MCL)

84

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
2013N/A00N/A
20142.73 ppm31310.1000 ppm - 6.13 ppm
2015N/A00N/A
20163.64 ppm2120ND - 7.65 ppm
20172.71 ppm14140.1000 ppm - 7.46 ppm
20182.13 ppm13130.150 ppm - 4.38 ppm
20192.33 ppm12120.176 ppm - 4.42 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
2014-01-06BF95192NOX1.84 ppm
2014-01-15BF99638NOX2.07 ppm
2014-01-16BG00211NOX0.900 ppm
2014-01-28BG04228IOC14.10 ppm
2014-01-28BG04228NOX4.10 ppm
2014-01-29BG04219NOX0.120 ppm
2014-01-29BG04659IOC11.59 ppm
2014-03-17GBG19879NOX2.97 ppm
2014-04-03BG27981NOX3.78 ppm
2014-04-03BG37981NOX3.78 ppm
2014-04-094561IOC10.200 ppm
2014-04-094561NOX0.200 ppm
2014-04-22BG35279NOX0.170 ppm
2014-04-25BG37305NOX4.61 ppm
2014-05-076132IOCR0.109 ppm
2014-05-076132NOX0.1000 ppm
2014-05-21BG47680NOX2.87 ppm
2014-06-04BG53346NOX2.08 ppm
2014-06-05BG53878IOC11.95 ppm
2014-06-05BG53878NOX1.95 ppm
2014-06-06BG54002NOX5.95 ppm
2014-06-17BG60666NOX5.34 ppm
2014-06-19BG62968NOX2.67 ppm
2014-06-30BG67304NOX4.74 ppm
2014-07-01BG68352NOX4.08 ppm
2014-07-01BG68349NOX6.13 ppm
2014-07-02BG68647NOX4.56 ppm
2014-07-30BG85048NOX4.40 ppm
2014-10-30BH34534NOX4.63 ppm
2014-11-21141121-0002IOC11.37 ppm
2014-11-21BH44966NOX1.37 ppm
2016-01-15BK53768NOX0.760 ppm
2016-01-27BK58484NOX3.20 ppm
2016-01-27BK58055IOCR0.0800 ppm
2016-01-27BK58485NOX3.30 ppm
2016-01-27BK58483NOX1.86 ppm
2016-03-18BK81669NOX7.65 ppm
2016-04-21BN17626NOX4.87 ppm
2016-05-12BN31364NOX1.93 ppm
2016-05-19BN35998NOX5.85 ppm
2016-05-24BN39642NOX2.78 ppm
2016-05-25BN40000NOX3.46 ppm
2016-06-22BN61158NOX7.60 ppm
2016-06-24BN62539NOX3.61 ppm
2016-07-01BN66354NOX6.53 ppm
2016-07-01BN66356NOX5.03 ppm
2016-07-22BN79282NOX5.66 ppm
2016-09-15BV16051NOX4.58 ppm
2016-09-29BV31669NOX2.12 ppm
2016-10-06BV40210NOX4.35 ppm
2016-10-11BV44061NOXND
2016-10-18BV56707NOX1.23 ppm
2017-01-06BX17339NOX7.46 ppm
2017-02-08BX57436NOX0.1000 ppm
2017-03-03BX79851NOX1.59 ppm
2017-03-08BX81787IOCR0.1000 ppm
2017-04-06BY00572NOX3.86 ppm
2017-04-20BY07159NOX3.80 ppm
2017-04-21BY07962NOX2.93 ppm
2017-05-30BY30818NOX3.39 ppm
2017-06-14BY39226NOX2.12 ppm
2017-06-23BY45937NOX2.08 ppm
2017-07-07BY54440NOX3.76 ppm
2017-07-07BY54441NOX0.660 ppm
2017-09-22BZ07174NOX2.03 ppm
2017-11-10BZ39757NOX4.04 ppm
2018-01-12BZ72528NOX0.740 ppm
2018-01-12BZ72529NOX1.66 ppm
2018-01-12BZ72527NOX4.38 ppm
2018-01-23BZ78886NOX0.150 ppm
2018-01-23BZ78887NOX0.150 ppm
2018-01-31BZ82949NOX3.55 ppm
2018-01-31BZ82691IOCR0.180 ppm
2018-03-02BZ97488NOX1.54 ppm
2018-04-19CA23517NOX3.22 ppm
2018-07-12CA891502.19 ppm
2018-07-13CA899032.82 ppm
2018-07-20CA947204.25 ppm
2018-12-10NOX 2005154182.84 ppm
2019-01-02NOX 2005173050.176 ppm
2019-01-10IOCR 2005184120.209 ppm
2019-01-15NOX 2005187790.224 ppm
2019-03-15NOX 2005248830.439 ppm
2019-03-22NOX 2005256132.16 ppm
2019-03-22NOX 2005256123.92 ppm
2019-05-30NOX 2005342444.42 ppm
2019-05-30NOX 2005342433.10 ppm
2019-07-02NOX 2005387824.34 ppm
2019-07-02NOX 2005387712.72 ppm
2019-07-18NOX 2005411472.27 ppm
2019-10-03NOX 2005513714.02 ppm