Nitrate
Westerly Water Department
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 | 1.30 ppm | 12 | 12 | 0.180 ppm - 2.50 ppm |
| 2015 | 1.30 ppm | 12 | 12 | 0.170 ppm - 2.81 ppm |
| 2016 | 1.30 ppm | 12 | 12 | 0.160 ppm - 4.23 ppm |
| 2017 | 1.20 ppm | 12 | 12 | 0.210 ppm - 2.73 ppm |
| 2018 | 1.48 ppm | 14 | 14 | 0.230 ppm - 3.25 ppm |
| 2019 | 1.50 ppm | 12 | 12 | 0.210 ppm - 3.39 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 |
|---|---|---|
| 2014-05-01 | BG39530-IOC | 1.01 ppm |
| 2014-05-01 | BG39529-IOC | 0.960 ppm |
| 2014-05-01 | BG39528-IOC | 2.47 ppm |
| 2014-05-02 | BG40111-IOC | 1.69 ppm |
| 2014-05-02 | BG40109-IOC | 1.000 ppm |
| 2014-05-06 | BG41004-IOC | 1.44 ppm |
| 2014-05-08 | BG42439-IOC | 1.50 ppm |
| 2014-05-13 | BG43968-IOC | 2.50 ppm |
| 2014-05-13 | BG43969-IOC | 0.910 ppm |
| 2014-05-14 | BG44525-IOC | 0.690 ppm |
| 2014-05-15 | BG45214-IOC | 0.180 ppm |
| 2014-05-15 | BG45216_IOC | 1.28 ppm |
| 2015-03-12 | BH82776_WL16_WL7 | 0.620 ppm |
| 2015-03-12 | BH82777_WL16_WL7 | 1.04 ppm |
| 2015-03-12 | BH82772_WL16_WL7 | 1.20 ppm |
| 2015-03-12 | BH82774_WL16_WL7 | 2.81 ppm |
| 2015-03-12 | BH82775_WL16_WL7 | 0.840 ppm |
| 2015-03-12 | BH82773_WL16_WL7 | 1.40 ppm |
| 2015-03-13 | BH83396_WL16_WL5 | 0.750 ppm |
| 2015-03-13 | BH83407_WL16_WL5 | 2.62 ppm |
| 2015-03-13 | BH83397_WL16_WL5 | 1.57 ppm |
| 2015-03-13 | BH83394_WL16_WL5 | 0.170 ppm |
| 2015-03-13 | BH83395_WL16_WL5 | 1.42 ppm |
| 2015-03-24 | BH87234_WL16_WL5 | 1.18 ppm |
| 2016-01-27 | BK58141_WL16 | 0.710 ppm |
| 2016-01-27 | BK58140_WL16 | 0.930 ppm |
| 2016-01-28 | BK58551_WL16 | 0.970 ppm |
| 2016-01-28 | BK58549_WL16 | 0.380 ppm |
| 2016-01-28 | BK58548_WL16 | 2.59 ppm |
| 2016-01-28 | BK58550_WL16 | 1.46 ppm |
| 2016-02-11 | BK64294_WL16 | 0.160 ppm |
| 2016-02-11 | BK64292_WL16 | 0.520 ppm |
| 2016-02-11 | BK64293_WL16 | 1.59 ppm |
| 2016-02-16 | BK65876_WL16 | 4.23 ppm |
| 2016-02-16 | BK65875_WL16 | 0.860 ppm |
| 2016-02-16 | BK65877_WL16 | 1.25 ppm |
| 2017-02-14 | BX60462_WL16_WL5 | 1.32 ppm |
| 2017-02-14 | BX60460_WL16_WL5 | 1.13 ppm |
| 2017-02-14 | BX60459_WL16_WL5 | 2.73 ppm |
| 2017-02-14 | BX60461_WL16_WL5 | 0.990 ppm |
| 2017-02-14 | BX60463_WL16_WL5 | 1.26 ppm |
| 2017-02-15 | BX63397_WL16_WL5 | 0.840 ppm |
| 2017-02-15 | BX63398_WL16_WL5 | 1.32 ppm |
| 2017-02-15 | BX63399_WL16_WL5 | 0.210 ppm |
| 2017-02-16 | BX69880_WL16_WL5 | 1.86 ppm |
| 2017-02-16 | BX69882_WL16_WL5 | 1.61 ppm |
| 2017-02-16 | BX69881_WL16_WL5 | 0.570 ppm |
| 2017-02-16 | BX69879_WL16_WL5 | 0.540 ppm |
| 2018-02-09 | BZ87032_WL16 | 1.40 ppm |
| 2018-02-09 | BZ87030_WL16 | 2.90 ppm |
| 2018-02-09 | BZ87031_WL16 | 0.810 ppm |
| 2018-02-20 | BZ91941_WL16 | 1.34 ppm |
| 2018-02-20 | BZ91943_WL16 | 1.68 ppm |
| 2018-02-20 | BZ91942_WL16 | 0.950 ppm |
| 2018-02-20 | BZ91944_WL16 | 1.42 ppm |
| 2018-02-20 | BZ91945_WL16 | 3.25 ppm |
| 2018-02-21 | BZ92670_WL16 | 0.230 ppm |
| 2018-02-21 | BZ92672_WL16 | 1.63 ppm |
| 2018-02-21 | BZ92671_WL16 | 0.760 ppm |
| 2018-03-06 | BZ98756-WL16_WL7 | 1.58 ppm |
| 2018-03-06 | BZ98755_WL16_WL7 | 0.600 ppm |
| 2018-04-27 | CA37843_WL16_WL5 | 2.15 ppm |
| 2019-03-04 | CC61974_WL16_WL5 | 1.22 ppm |
| 2019-03-04 | CC61978_WL16_WL5 | 1.40 ppm |
| 2019-03-04 | CC61977_WL16_WL5 | 0.630 ppm |
| 2019-03-04 | CC61972_WL16_WL5 | 2.57 ppm |
| 2019-03-04 | CC61973_WL16_WL5 | 1.000 ppm |
| 2019-03-04 | CC61975_WL16_WL5 | 2.17 ppm |
| 2019-03-04 | CC61976_WL16_WL5 | 3.39 ppm |
| 2019-03-06 | CC62789_WL16_WL5 | 1.80 ppm |
| 2019-03-06 | CC62790_WL16_WL5 | 0.210 ppm |
| 2019-03-06 | CC62791_WL16_WL5 | 1.41 ppm |
| 2019-09-04 | CD97213_WL16 | 1.42 ppm |
| 2019-09-04 | CD97212_WL16 | 0.790 ppm |