Nitrate
Nob Hill Water Association
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 | 0.618 ppm | 5 | 4 | ND - 2.16 ppm |
| 2015 | 0.238 ppm | 5 | 4 | ND - 0.530 ppm |
| 2016 | 0.448 ppm | 5 | 4 | ND - 1.23 ppm |
| 2017 | 0.336 ppm | 5 | 4 | ND - 0.550 ppm |
| 2018 | 0.374 ppm | 5 | 4 | ND - 0.900 ppm |
| 2019 | 0.292 ppm | 5 | 4 | ND - 0.560 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 |
|---|---|---|
| 2014-08-26 | 21359 | 0.1000 ppm |
| 2014-08-26 | 21360 | ND |
| 2014-08-26 | 21361 | 0.520 ppm |
| 2014-08-26 | 21362 | 0.310 ppm |
| 2014-08-26 | 21358 | 2.16 ppm |
| 2015-08-04 | 22695 | 0.260 ppm |
| 2015-08-04 | 22699 | 0.320 ppm |
| 2015-08-04 | 22696 | 0.0800 ppm |
| 2015-08-04 | 22698 | 0.530 ppm |
| 2015-08-04 | 22697 | ND |
| 2016-07-13 | ND | |
| 2016-07-13 | 0.190 ppm | |
| 2016-07-13 | 0.320 ppm | |
| 2016-08-09 | 0.500 ppm | |
| 2016-08-09 | 1.23 ppm | |
| 2017-07-10 | 0.340 ppm | |
| 2017-07-10 | 0.540 ppm | |
| 2017-07-10 | ND | |
| 2017-07-10 | 0.250 ppm | |
| 2017-07-10 | 0.550 ppm | |
| 2018-07-31 | 0.330 ppm | |
| 2018-07-31 | 0.120 ppm | |
| 2018-07-31 | ND | |
| 2018-07-31 | 0.520 ppm | |
| 2018-07-31 | 0.900 ppm | |
| 2019-07-02 | 0.370 ppm | |
| 2019-07-02 | 0.440 ppm | |
| 2019-07-02 | 0.560 ppm | |
| 2019-07-02 | 0.0900 ppm | |
| 2019-07-02 | ND |