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EWG's Tap Water Database — 2019 UPDATE

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Perchlorate

Los Angeles County WW District 4 & 34-Lancaster

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.

 

58

Samples

0

Samples exceeding legal limit (MCL)

0

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
2012ND40ND
2013ND230ND
2014ND20ND
2015ND20ND
2016ND200ND
2017ND70ND

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
2012-01-245442-053-0903ND
2012-01-245442-054-0937ND
2012-04-125442-054-1015ND
2012-11-085442-062-1038ND
2013-03-115442-028-1205ND
2013-03-115442-016-1140ND
2013-03-115442-011-0931ND
2013-03-115442-023-1045ND
2013-03-115442-062-1130ND
2013-03-125442-036-1106ND
2013-03-135442-035-1159ND
2013-03-135442-035-0852ND
2013-03-195442-026-0925ND
2013-03-195442-002-1135ND
2013-03-195442-093-0844ND
2013-04-035442-063-0835ND
2013-04-095442-070-0945ND
2013-05-215442-040-0908ND
2013-06-045442-041-0910ND
2013-06-045442-048-0934ND
2013-06-105442-055-0922ND
2013-06-125442-095-0859ND
2013-07-165442-045-1050ND
2013-07-165442-094-0859ND
2013-07-175442-067-1050ND
2013-07-235442-071-1047ND
2013-07-245442-069-1002ND
2014-03-265442-055-1034ND
2014-05-135442-037-1138ND
2015-01-285442-053-0915ND
2015-04-135442-054-0940ND
2016-01-195442-035-0950ND
2016-01-195442-040-0945ND
2016-01-255442-028-0840ND
2016-01-255442-048-0940ND
2016-01-255442-062-0930ND
2016-02-095442-070-1110ND
2016-02-095442-069-1010ND
2016-02-095442-068-1025ND
2016-02-095442-016-1028ND
2016-02-105442-071-1125ND
2016-03-095442-023-1041ND
2016-03-285442-011-1138ND
2016-03-285442-067-0856ND
2016-03-285442-055-1126ND
2016-04-205442-041-0934ND
2016-04-205442-026-1016ND
2016-06-085442-036-0945ND
2016-06-275442-095-1050ND
2016-06-275442-094-1125ND
2016-09-135442-093-0915ND
2017-11-219590-055-0940ND
2017-11-219590-045-0935ND
2017-11-219590-063-1010ND
2017-11-299590-037-1100ND
2017-12-279590-094-0910ND
2017-12-279590-063-1010ND
2017-12-279590-093-1115ND