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EWG's Tap Water Database — 2019 UPDATE

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Perchlorate

San Gabriel County 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.

Click here to read more about perchlorate.

 

61

Samples

0

Samples exceeding legal limit (MCL)

0

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
2012ND140ND
2013ND60ND
2014ND230ND
2015ND50ND
2016ND80ND
2017ND50ND

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
2012-01-043761-001-1125ND
2012-02-073761-001-1005ND
2012-03-063761-001-1030ND
2012-04-043761-001-0920ND
2012-05-013761-001-1135ND
2012-06-063761-001-0850ND
2012-07-033761-001-1040ND
2012-07-179588-009-0915ND
2012-07-179588-011-1015ND
2012-07-179588-010-0930ND
2012-07-179588-007-0945ND
2012-08-073761-001-0000ND
2012-10-023761-001-1105ND
2012-11-073761-001-1120ND
2013-05-243761-020-1125ND
2013-07-159588-009-0950ND
2013-07-159588-007-0910ND
2013-07-159588-010-1005ND
2013-07-159588-011-0935ND
2013-08-139588-001-1015ND
2014-03-123761-020-1100ND
2014-03-173761-020-1110ND
2014-03-253761-020-1005ND
2014-04-013761-020-1050ND
2014-04-083761-020-1010ND
2014-04-153761-020-1005ND
2014-04-223761-020-1015ND
2014-04-293761-020-0930ND
2014-05-063761-020-1025ND
2014-05-133761-020-1005ND
2014-05-203761-020-0955ND
2014-05-273761-020-1015ND
2014-06-023761-020-1045ND
2014-06-103761-020-1005ND
2014-06-173761-020-1020ND
2014-06-173761-020-1010ND
2014-06-243761-020-0725ND
2014-07-149588-009-0900ND
2014-07-149588-011-0945ND
2014-07-149588-010-0915ND
2014-07-149588-007-0930ND
2014-07-159588-001-1000ND
2014-12-059588-020-0910ND
2015-07-169588-001-0940ND
2015-07-169588-011-1020ND
2015-07-169588-010-1000ND
2015-07-169588-007-0920ND
2015-10-099588-020-0950ND
2016-01-139588-011-0925ND
2016-01-139588-010-0910ND
2016-01-139588-007-0950ND
2016-07-189588-007-1015ND
2016-07-189588-009-0925ND
2016-07-189588-010-0935ND
2016-07-189588-011-0950ND
2016-10-199588-020-0915ND
2017-07-179588-011-0945ND
2017-07-179588-010-0925ND
2017-07-179588-007-1010ND
2017-07-179588-009-0905ND
2017-10-189588-020-0950ND