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EWG's Tap Water Database — 2021 UPDATE

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Perchlorate

Downey Water Department

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.

MORE ABOUT THIS CONTAMINANT

 

118

Samples

0

Samples exceeding legal limit (MCL)

0

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
2014ND200ND
2015ND200ND
2016ND180ND
2017ND200ND
2018ND220ND
2019ND180ND

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
2014-02-132706-005-0934ND
2014-02-132706-007-0958ND
2014-02-132706-009-0804ND
2014-02-132706-010-0749ND
2014-02-132706-011-0838ND
2014-02-132706-012-1021ND
2014-02-132706-014-1045ND
2014-02-132706-016-0820ND
2014-02-132706-017-1105ND
2014-02-132706-018-1123ND
2014-02-132706-019-0727ND
2014-02-132706-020-0708ND
2014-02-132706-021-0633ND
2014-02-132706-024-0652ND
2014-02-132706-025-0518ND
2014-02-132706-026-0619ND
2014-02-132706-029-0559ND
2014-02-132706-030-0535ND
2014-02-132706-032-0859ND
2014-02-132706-033-1203ND
2015-02-122706-005-1028ND
2015-02-122706-007-0921ND
2015-02-122706-009-0753ND
2015-02-122706-010-0818ND
2015-02-122706-011-0857ND
2015-02-122706-012-0736ND
2015-02-122706-014-1133ND
2015-02-122706-016-0836ND
2015-02-122706-017-1228ND
2015-02-122706-019-1259ND
2015-02-122706-020-1322ND
2015-02-122706-032-1106ND
2015-02-122706-033-1006ND
2015-02-132706-021-0811ND
2015-02-132706-024-0824ND
2015-02-132706-025-0700ND
2015-02-132706-026-0748ND
2015-02-132706-029-0732ND
2015-02-132706-030-0716ND
2015-03-102706-018-0735ND
2016-02-232706-017-1042ND
2016-02-232706-018-1058ND
2016-02-232706-019-1022ND
2016-02-232706-020-0954ND
2016-02-232706-024-0935ND
2016-02-232706-025-0725ND
2016-02-232706-026-0859ND
2016-02-232706-029-0835ND
2016-02-232706-030-0758ND
2016-03-092706-005-0948ND
2016-03-092706-007-0857ND
2016-03-092706-009-0738ND
2016-03-092706-011-0759ND
2016-03-092706-012-1011ND
2016-03-092706-014-1038ND
2016-03-092706-016-0709ND
2016-03-092706-032-0827ND
2016-04-072706-033-0803ND
2017-01-102706-005-0856ND
2017-01-102706-007-1050ND
2017-01-102706-009-0826ND
2017-01-102706-011-0959ND
2017-01-102706-032-1030ND
2017-01-112706-012-1012ND
2017-01-112706-014-1115ND
2017-01-112706-016-0952ND
2017-01-112706-017-1103ND
2017-01-112706-018-1038ND
2017-01-112706-020-0931ND
2017-01-112706-024-0903ND
2017-01-112706-025-0725ND
2017-01-112706-026-0832ND
2017-01-112706-030-0802ND
2017-02-282706-010-0742ND
2017-02-282706-021-2040ND
2017-04-132706-029-0845ND
2017-04-132706-033-0915ND
2017-05-189588-019-1400ND
2018-02-139588-005-1105ND
2018-02-139588-007-0900ND
2018-02-139588-009-0930ND
2018-02-139588-010-0945ND
2018-02-139588-011-1200ND
2018-02-139588-014-1255ND
2018-02-139588-016-1132ND
2018-02-139588-032-1020ND
2018-02-139588-033-1220ND
2018-02-149588-017-1136ND
2018-02-149588-020-1206ND
2018-02-149588-024-1226ND
2018-02-149588-026-1059ND
2018-02-149588-029-1039ND
2018-02-149588-030-1020ND
2018-02-219588-018-0925ND
2018-02-219588-019-1000ND
2018-02-219588-021-1047ND
2018-03-269588-025-1035ND
2018-08-019588-012-0750ND
2018-10-239588-018-1314ND
2018-12-119588-012-1045ND
2019-01-159588-032-0755ND
2019-01-249588-025-0730ND
2019-01-249588-029-0905ND
2019-01-249588-030-0822ND
2019-01-259588-005-1048ND
2019-01-259588-009-1026ND
2019-01-259588-010-1008ND
2019-01-259588-020-0938ND
2019-01-259588-021-0840ND
2019-01-259588-026-0806ND
2019-01-309588-011-1030ND
2019-01-309588-019-0820ND
2019-01-309588-033-0735ND
2019-01-319588-014-1000ND
2019-01-319588-016-0930ND
2019-01-319588-017-1015ND
2019-01-319588-024-0820ND
2019-09-309588-033-0830ND