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EWG's Tap Water Database — 2021 UPDATE

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Perchlorate

Placer County Water Agency - Foothill

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.

Click here to read more about perchlorate.

 

18

Samples

0

Samples exceeding legal limit (MCL)

0

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
2014ND30ND
2015ND20ND
2016ND40ND
2017ND30ND
2018ND30ND
2019ND30ND

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 Lab ID Result
2014-08-205810-007-1200ND
2014-08-205810-002-1010ND
2014-12-299590-014-0955ND
2015-08-115810-002-1000ND
2015-08-115810-007-1305ND
2016-03-301233-014-1626ND
2016-08-031233-014-1045ND
2016-08-171233-002-1215ND
2016-08-171233-007-0945ND
2017-08-081233-007-0900ND
2017-08-081233-002-1120ND
2017-08-221233-014-1040ND
2018-10-191233-007-0800ND
2018-10-191233-002-1000ND
2018-10-301233-014-0840ND
2019-08-271233-002-1135ND
2019-09-091233-007-1330ND
2019-09-121233-014-1150ND