Nitrate
CTWC - Shoreline Region-Guilford System
Nitrate, a fertilizer chemical, frequently contaminates drinking water due to agricultural and urban runoff, and discharges from municipal wastewater treatment plants and septic tanks. Excessive nitrate in water can cause oxygen deprivation in infants and increase the risk of cancer. Click here to read more about nitrate.
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 | 1.11 ppm | 23 | 18 | ND - 3.30 ppm |
| 2015 | 1.25 ppm | 16 | 14 | ND - 2.81 ppm |
| 2016 | 0.907 ppm | 17 | 13 | ND - 2.83 ppm |
| 2017 | 0.955 ppm | 10 | 10 | 0.0600 ppm - 2.31 ppm |
| 2018 | 0.805 ppm | 15 | 15 | 0.0250 ppm - 2.71 ppm |
| 2019 | 0.481 ppm | 23 | 23 | 0.0150 ppm - 3.37 ppm |
ppm = parts per million
State and national drinking water standards and health guidelines
EWG Health Guideline 0.14 ppm
The EWG Health Guideline of 0.14 ppm for nitrate was defined by EWG . This health guideline protects against cancer and harm to fetal growth and development.
EPA Maximum Contaminant
Level (MCL) 10 ppm
The legal limit for nitrate, established in 1962, was developed to protect infants from acute methemoglobinemia, a life-threatening disorder of oxygen transport in the body. This limit does not fully protect against the risk of cancer and harm to the developing fetus.
ppm = parts per million
All test results
| Date | Lab ID | Result |
|---|---|---|
| 2014-01-06 | 142NOX | 0.200 ppm |
| 2014-01-29 | 140130CWCDNOX | 0.240 ppm |
| 2014-01-29 | 140130CWCEIOC1 | 0.190 ppm |
| 2014-01-29 | 91886NOX | 2.52 ppm |
| 2014-01-29 | 91887NOX | 2.62 ppm |
| 2014-02-06 | 91982NOX | 2.24 ppm |
| 2014-02-24 | 92178NOX | 2.04 ppm |
| 2014-03-05 | 2669IOC1 | 3.30 ppm |
| 2014-03-05 | 2673IOC1 | 2.80 ppm |
| 2014-03-05 | 2674IOC1 | 2.40 ppm |
| 2014-03-05 | 2676IOC1 | 2.00 ppm |
| 2014-04-01 | 4079NOX | 0.1000 ppm |
| 2014-06-12 | 8366IOC1 | 0.800 ppm |
| 2014-06-12 | 8367IOC1 | 1.000 ppm |
| 2014-06-12 | 93879NOX | 1.000 ppm |
| 2014-06-12 | 93880NOX | 0.800 ppm |
| 2014-06-12 | 93881NOX | ND |
| 2014-07-22 | 10660NOX | ND |
| 2014-08-13 | 140915-0115IOC1 | ND |
| 2014-08-13 | 141007-0044IOC1 | 0.680 ppm |
| 2014-08-13 | BG93593NOX | ND |
| 2014-08-13 | BG93595NOX | 0.680 ppm |
| 2014-11-20 | BH44138NOX | ND |
| 2015-02-11 | BH72588NOX | 2.01 ppm |
| 2015-02-11 | BH72586NOX | 1.82 ppm |
| 2015-02-11 | BH72587NOX | 2.76 ppm |
| 2015-02-11 | BH72589NOX | 2.23 ppm |
| 2015-02-12 | BH73177NOX | 0.190 ppm |
| 2015-04-01 | BH90872NOX | 0.170 ppm |
| 2015-06-02 | BJ24597NOX | ND |
| 2015-06-02 | BJ24602NOX | 2.81 ppm |
| 2015-06-02 | BJ24619NOX | 1.03 ppm |
| 2015-06-02 | BJ24600NOX | 2.05 ppm |
| 2015-06-02 | BJ24617NOX | 1.01 ppm |
| 2015-06-03 | BJ25406NOX | 1.02 ppm |
| 2015-06-03 | BJ25404NOX | 2.15 ppm |
| 2015-07-07 | BJ42388NOX | 0.0500 ppm |
| 2015-07-27 | BJ63961NOX | 0.680 ppm |
| 2015-10-07 | BK03851NOX | ND |
| 2016-01-11 | BK50861NOX | 1.86 ppm |
| 2016-01-11 | BK50864NOX | 1.70 ppm |
| 2016-01-12 | BK51721NOX | 0.110 ppm |
| 2016-01-19 | BK54776NOX | 0.900 ppm |
| 2016-01-19 | BK54777NOX | 2.64 ppm |
| 2016-01-27 | BK58354NOX | 0.140 ppm |
| 2016-02-11 | BK64352NOX | 0.160 ppm |
| 2016-03-14 | BK78121NOX | ND |
| 2016-04-06 | BN07656NOX | 0.0700 ppm |
| 2016-06-01 | BN44876NOX | 1.10 ppm |
| 2016-07-06 | BN67632NOX | ND |
| 2016-07-12 | BN71483NOX | 1.32 ppm |
| 2016-07-12 | BN71475NOX | 0.910 ppm |
| 2016-07-13 | BN72281NOX | ND |
| 2016-07-13 | BN72289NOX | 2.83 ppm |
| 2016-07-13 | BN72288NOX | 1.68 ppm |
| 2016-10-12 | BV46547NOX | ND |
| 2017-01-17 | BX30298NOX | 0.0600 ppm |
| 2017-01-17 | BX30299NOX | 1.61 ppm |
| 2017-01-18 | BX31347NOX | 0.120 ppm |
| 2017-01-30 | BX40966NOX | 1.31 ppm |
| 2017-03-08 | BX82062NOX | 2.28 ppm |
| 2017-03-08 | BX82063NOX | 2.31 ppm |
| 2017-04-03 | BX97712NOX | 0.1000 ppm |
| 2017-07-17 | BY61083NOX | 0.120 ppm |
| 2017-10-24 | BZ27135NOX | 1.47 ppm |
| 2017-12-04 | BZ49884NOX | 0.170 ppm |
| 2018-01-16 | BZ73475NOX | 0.280 ppm |
| 2018-03-30 | CA11466NOX | 0.170 ppm |
| 2018-06-04 | CA63507NOX | 0.200 ppm |
| 2018-06-13 | CA69714NOX | 0.0500 ppm |
| 2018-06-13 | CA69718NOX | 2.71 ppm |
| 2018-06-13 | CA69716NOX | 1.01 ppm |
| 2018-06-13 | CA69715NOX | 2.17 ppm |
| 2018-06-13 | CA69717NOX | 1.76 ppm |
| 2018-06-20 | CA75544NOX | 0.260 ppm |
| 2018-09-19 | NOX 200506169 | 0.125 ppm |
| 2018-10-09 | NOX 200508367 | 0.124 ppm |
| 2018-11-08 | NOX 200512198 | 0.0250 ppm |
| 2018-11-21 | NOX 200513547 | 1.50 ppm |
| 2018-11-26 | NOX 200513931 | 1.60 ppm |
| 2018-12-10 | NOX 200515324 | 0.0780 ppm |
| 2019-01-07 | NOX 200517748 | 0.118 ppm |
| 2019-01-30 | NOX 200520057 | 0.123 ppm |
| 2019-02-06 | NOX 200520859 | 0.155 ppm |
| 2019-02-07 | NOX 200521039 | 0.159 ppm |
| 2019-03-05 | NOX 200523518 | 0.126 ppm |
| 2019-04-02 | NOX 200526702 | 0.108 ppm |
| 2019-04-08 | NOX 200527439 | 0.101 ppm |
| 2019-05-06 | NOX 200530919 | 0.0480 ppm |
| 2019-06-05 | NOX 200535054 | 0.0620 ppm |
| 2019-06-24 | NOX 200537625 | 0.0150 ppm |
| 2019-07-09 | NOX 200539960 | 0.123 ppm |
| 2019-07-10 | NOX 200539996 | 0.426 ppm |
| 2019-07-10 | NOX 200539998 | 0.426 ppm |
| 2019-07-16 | NOX 200541091 | 3.37 ppm |
| 2019-07-16 | NOX 200540648 | 0.924 ppm |
| 2019-07-16 | NOX 200540644 | 2.13 ppm |
| 2019-08-05 | NOX 200545065 | 0.0740 ppm |
| 2019-09-11 | NOX 200548435 | 0.0400 ppm |
| 2019-09-17 | NOX 200549238 | 1.02 ppm |
| 2019-09-18 | NOX 200549465 | 1.33 ppm |
| 2019-10-02 | NOX 200551087 | 0.0260 ppm |
| 2019-11-12 | NOX 200556637 | 0.0620 ppm |
| 2019-12-05 | NOX 200559108 | 0.0980 ppm |