Perchlorate
Centerville Osterville Marstons Mills WD
Perchlorate, a component of rocket fuel, occurs both naturally and as a synthetic chemical. Ingested perchlorate interferes with thyroid function. Exposure to perchlorate during pregnancy and childhood can impair cognitive development. Read More.
According to the EPA, perchlorate likely contaminates the water of more than 16 million Americans. Perchlorate interferes with iodine uptake in the thyroid, which can result in reduced thyroid hormones and an impact on metabolism, physical development and cognitive development. Children and developing fetuses are the most at risk from perchlorate contamination.
Perchlorate is the only unregulated contaminant for which the EPA has attempted to set a federal drinking water standard since 1996. However, the agency has yet to propose a draft limit for this contaminant. Perchlorate in drinking water is regulated in Arizona, California, Massachusetts, New Jersey, New York and Texas. California set a public health goal of 1 part per billion for perchlorate in 2015.
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 | 0.224 ppb | 19 | 12 | ND - 1.10 ppb |
| 2015 | 0.476 ppb | 5 | 5 | 0.300 ppb - 0.740 ppb |
| 2016 | 0.460 ppb | 5 | 4 | ND - 0.670 ppb |
| 2017 | 0.0855 ppb | 20 | 6 | ND - 0.360 ppb |
| 2018 | ND | 2 | 0 | ND |
| 2019 | ND | 3 | 0 | ND |
ppb = parts per billion
State and national drinking water standards and health guidelines
EWG Health Guideline 1 ppb
The EWG Health Guideline of 1 ppb for perchlorate was defined by the California Office of Environmental Health Hazard Assessment as a public health goal, the level of a drinking water contaminant that does not pose a significant health risk. This health guideline protects against hormone disruption.
ppb = parts per billion
All test results
| Date | Result |
|---|---|
| 2014-09-10 | 0.360 ppb |
| 2014-09-10 | 0.170 ppb |
| 2014-09-10 | 0.260 ppb |
| 2014-09-10 | 0.820 ppb |
| 2014-09-10 | 0.220 ppb |
| 2014-09-10 | 0.0500 ppb |
| 2014-09-10 | ND |
| 2014-09-10 | 0.140 ppb |
| 2014-09-10 | ND |
| 2014-09-10 | ND |
| 2014-09-10 | ND |
| 2014-09-10 | ND |
| 2014-09-10 | ND |
| 2014-09-10 | ND |
| 2014-09-11 | 0.240 ppb |
| 2014-09-11 | 0.250 ppb |
| 2014-09-11 | 0.370 ppb |
| 2014-09-25 | 1.10 ppb |
| 2014-12-17 | 0.280 ppb |
| 2015-02-26 | 0.740 ppb |
| 2015-06-10 | 0.330 ppb |
| 2015-08-10 | 0.590 ppb |
| 2015-08-10 | 0.420 ppb |
| 2015-10-27 | 0.300 ppb |
| 2016-01-27 | ND |
| 2016-06-23 | 0.670 ppb |
| 2016-08-18 | 0.530 ppb |
| 2016-08-18 | 0.520 ppb |
| 2016-11-23 | 0.580 ppb |
| 2017-07-27 | 0.270 ppb |
| 2017-08-23 | 0.120 ppb |
| 2017-08-23 | ND |
| 2017-08-23 | ND |
| 2017-08-23 | ND |
| 2017-08-23 | ND |
| 2017-08-23 | 0.260 ppb |
| 2017-08-23 | ND |
| 2017-08-23 | 0.340 ppb |
| 2017-08-23 | ND |
| 2017-08-23 | ND |
| 2017-08-23 | ND |
| 2017-08-23 | ND |
| 2017-08-23 | ND |
| 2017-08-23 | ND |
| 2017-08-23 | 0.360 ppb |
| 2017-08-23 | 0.360 ppb |
| 2017-08-23 | ND |
| 2017-08-23 | ND |
| 2017-10-26 | ND |
| 2018-08-09 | ND |
| 2018-08-16 | ND |
| 2019-09-03 | ND |
| 2019-09-03 | ND |
| 2019-09-03 | ND |