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EWG's Tap Water Database — 2021 UPDATE

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Perchlorate

Lake Arrowhead CSD

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

 

52

Samples

0

Samples exceeding legal limit (MCL)

0

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
2014ND80ND
2015ND80ND
2016ND70ND
2017ND160ND
2018ND70ND
2019ND60ND

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
2014-06-263761-004-1108ND
2014-07-093761-013-1204ND
2014-07-093761-012-1228ND
2014-07-093761-010-1221ND
2014-07-093761-009-1238ND
2014-07-093761-007-1253ND
2014-07-093761-006-1216ND
2014-07-093761-002-0843ND
2015-04-223761-004-1110ND
2015-07-083761-002-1007ND
2015-07-083761-007-1112ND
2015-07-083761-006-1047ND
2015-07-083761-009-1105ND
2015-07-083761-011-1042ND
2015-07-083761-012-1056ND
2015-08-123761-013-1010ND
2016-06-083761-004-1057ND
2016-07-133761-002-1302ND
2016-07-143761-013-1010ND
2016-07-143761-012-1033ND
2016-07-143761-006-1027ND
2016-07-143761-007-1052ND
2016-07-143761-009-1043ND
2017-02-233761-004-0900ND
2017-04-193761-002-0955ND
2017-04-193761-005-0921ND
2017-06-073761-005-0924ND
2017-06-073761-002-1221ND
2017-06-073761-604-1152ND
2017-07-183761-002-1136ND
2017-07-193761-009-0837ND
2017-07-193761-007-0905ND
2017-07-193761-012-0936ND
2017-07-193761-006-0920ND
2017-07-193761-013-0917ND
2017-07-193761-013-1011ND
2017-09-063761-002-0900ND
2017-09-063761-004-1204ND
2017-09-063761-604-1315ND
2018-02-143761-004-0925ND
2018-05-233761-007-0930ND
2018-07-113761-013-0932ND
2018-07-113761-013-0917ND
2018-07-113761-012-0955ND
2018-07-113761-006-0944ND
2018-08-153761-002-0855ND
2019-02-273761-004-1000ND
2019-07-103761-002-0843ND
2019-07-173761-013-1000ND
2019-07-173761-012-1025ND
2019-07-173761-009-1030ND
2019-07-173761-006-1018ND