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EWG's Tap Water Database — 2021 UPDATE

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Perchlorate

Sweetwater Authority

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

 

73

Samples

0

Samples exceeding legal limit (MCL)

0

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
2014ND140ND
2015ND120ND
2016ND120ND
2017ND110ND
2018ND120ND
2019ND120ND

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
2014-01-073761-005-1430ND
2014-02-253761-019-0915ND
2014-02-253761-018-0855ND
2014-02-253761-017-0930ND
2014-02-253761-007-1110ND
2014-02-253761-004-0910ND
2014-02-253761-005-1115ND
2014-03-113761-005-1315ND
2014-07-293761-019-0915ND
2014-07-293761-018-0935ND
2014-07-293761-017-0820ND
2014-07-293761-007-1230ND
2014-07-293761-005-1240ND
2014-07-293761-004-0910ND
2015-01-273761-019-0930ND
2015-01-273761-017-0820ND
2015-01-273761-007-1240ND
2015-01-273761-018-0950ND
2015-01-273761-005-1250ND
2015-01-273761-004-0920ND
2015-08-253761-019-1000ND
2015-08-253761-018-1005ND
2015-08-253761-017-0815ND
2015-08-253761-004-0955ND
2015-08-253761-007-0750ND
2015-08-253761-005-0740ND
2016-01-273761-005-0740ND
2016-01-273761-019-1005ND
2016-01-273761-018-1010ND
2016-01-273761-017-0950ND
2016-01-273761-007-0735ND
2016-01-273761-004-1000ND
2016-07-263761-007-1300ND
2016-07-263761-017-0840ND
2016-07-263761-005-1255ND
2016-07-263761-004-1035ND
2016-07-263761-018-1055ND
2016-07-263761-019-1040ND
2017-01-313761-004-0955ND
2017-01-313761-005-1130ND
2017-01-313761-018-0905ND
2017-01-313761-019-0950ND
2017-01-313761-007-1135ND
2017-10-033761-004-0945ND
2017-10-033761-007-1135ND
2017-10-033761-005-1130ND
2017-10-033761-019-0950ND
2017-10-033761-017-1130ND
2017-10-033761-018-1005ND
2018-01-303761-007-0730ND
2018-01-303761-004-1025ND
2018-01-303761-017-1110ND
2018-01-303761-018-1010ND
2018-01-303761-019-1030ND
2018-01-303761-005-0735ND
2018-11-273761-004-1012ND
2018-11-273761-017-0839ND
2018-11-273761-019-1007ND
2018-11-273761-018-1000ND
2018-11-283761-007-0745ND
2018-11-283761-005-0740ND
2019-02-273761-019-1240ND
2019-02-273761-018-1250ND
2019-02-273761-017-1015ND
2019-02-273761-004-1218ND
2019-02-283761-007-0820ND
2019-02-283761-005-0800ND
2019-08-273761-017-0815ND
2019-08-273761-004-1000ND
2019-08-273761-019-1005ND
2019-08-273761-018-1035ND
2019-08-283761-007-0730ND
2019-08-283761-005-0730ND