Nitrate
Clear Lake City Water Authority
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 |
|---|---|---|---|---|
| 2013 | N/A | 0 | 0 | N/A |
| 2014 | 0.389 ppm | 7 | 7 | 0.01000 ppm - 0.710 ppm |
| 2015 | 0.247 ppm | 7 | 7 | 0.0800 ppm - 0.440 ppm |
| 2016 | 0.360 ppm | 7 | 7 | 0.01000 ppm - 0.580 ppm |
| 2017 | 0.503 ppm | 7 | 7 | 0.0200 ppm - 0.850 ppm |
| 2018 | 0.493 ppm | 6 | 6 | 0.0400 ppm - 0.780 ppm |
| 2019 | 0.598 ppm | 6 | 5 | ND - 0.820 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 |
|---|---|---|
| 2014-02-26 | AC44657 | 0.570 ppm |
| 2014-02-26 | AC44658 | 0.640 ppm |
| 2014-02-26 | AC44634 | 0.560 ppm |
| 2014-04-22 | AC51305 | 0.710 ppm |
| 2014-06-24 | AC57729 | 0.01000 ppm |
| 2014-06-24 | AC57728 | 0.0300 ppm |
| 2014-06-24 | AC57714 | 0.200 ppm |
| 2015-01-20 | AC76689 | 0.0800 ppm |
| 2015-01-20 | AC76700 | 0.290 ppm |
| 2015-01-20 | AC76702 | 0.320 ppm |
| 2015-01-20 | AC76699 | 0.290 ppm |
| 2015-01-20 | AC76687 | 0.440 ppm |
| 2015-01-20 | AC76690 | 0.0800 ppm |
| 2015-01-20 | AC76688 | 0.230 ppm |
| 2016-01-19 | AD18441 | 0.310 ppm |
| 2016-01-19 | AD18440 | 0.0300 ppm |
| 2016-01-19 | AD18442 | 0.560 ppm |
| 2016-01-19 | AD18443 | 0.480 ppm |
| 2016-01-19 | AD18444 | 0.580 ppm |
| 2016-06-20 | AD41072 | 0.01000 ppm |
| 2016-06-20 | AD41073 | 0.550 ppm |
| 2017-01-19 | AD65596 | 0.510 ppm |
| 2017-03-08 | AD73854 | 0.820 ppm |
| 2017-03-08 | AD73855 | 0.800 ppm |
| 2017-03-08 | AD73899 | 0.0200 ppm |
| 2017-03-08 | AD73902 | 0.480 ppm |
| 2017-03-08 | AD73904 | 0.850 ppm |
| 2017-10-25 | AE02027 | 0.0400 ppm |
| 2018-02-20 | AE14297 | 0.450 ppm |
| 2018-03-12 | AE17713 | 0.660 ppm |
| 2018-03-12 | AE17710 | 0.560 ppm |
| 2018-03-12 | AE17711 | 0.780 ppm |
| 2018-03-12 | AE17712 | 0.470 ppm |
| 2018-04-24 | AE23612 | 0.0400 ppm |
| 2019-02-27 | AE56150 | 0.750 ppm |
| 2019-02-27 | AE56145 | 0.690 ppm |
| 2019-02-27 | AE56149 | ND |
| 2019-02-27 | AE56147 | 0.690 ppm |
| 2019-02-27 | AE56146 | 0.820 ppm |
| 2019-02-27 | AE56148 | 0.640 ppm |