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EWG's Tap Water Database — 2021 UPDATE

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Perchlorate

San Juan Basin 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

 

114

Samples

0

Samples exceeding legal limit (MCL)

0

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
2014ND200ND
2015ND280ND
2016ND140ND
2017ND140ND
2018ND130ND
2019ND250ND

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
2014-02-119590-010-1058ND
2014-03-049590-001-0940ND
2014-03-049590-002-1015ND
2014-03-049590-003-1039ND
2014-03-049590-004-1105ND
2014-03-049590-005-1120ND
2014-03-049590-006-0830ND
2014-03-049590-014-0905ND
2014-03-049590-015-0750ND
2014-05-069590-010-1340ND
2014-08-059590-003-1000ND
2014-08-059590-004-1035ND
2014-08-059590-005-1105ND
2014-08-059590-006-0920ND
2014-08-059590-014-0835ND
2014-08-059590-015-0750ND
2014-08-129590-010-1005ND
2014-09-039590-001-1300ND
2014-09-239590-002-1315ND
2014-11-119590-010-0748ND
2015-02-039590-002-0940ND
2015-02-039590-003-1025ND
2015-02-039590-004-1044ND
2015-02-039590-005-1120ND
2015-02-039590-006-0900ND
2015-02-109590-010-1300ND
2015-05-139590-010-1044ND
2015-08-129590-001-1013ND
2015-08-129590-002-0949ND
2015-08-129590-003-0955ND
2015-08-129590-004-1005ND
2015-08-129590-005-1020ND
2015-08-129590-006-1045ND
2015-08-129590-010-0916ND
2015-08-129590-014-1055ND
2015-08-129590-015-1108ND
2015-08-249590-002-1308ND
2015-08-249590-003-1313ND
2015-08-249590-004-1319ND
2015-08-259590-001-0816ND
2015-08-259590-005-0833ND
2015-08-259590-006-0805ND
2015-08-259590-014-0755ND
2015-08-259590-015-0708ND
2015-11-099590-010-0945ND
2015-12-229590-001-1135ND
2015-12-229590-014-1149ND
2015-12-229590-015-1300ND
2016-02-019590-010-1121ND
2016-02-089590-001-1000ND
2016-02-089590-002-1027ND
2016-02-089590-003-1040ND
2016-02-089590-004-1052ND
2016-02-089590-005-1110ND
2016-02-089590-006-0840ND
2016-02-089590-014-0852ND
2016-02-089590-015-0909ND
2016-05-099590-010-0947ND
2016-08-019590-002-0836ND
2016-08-019590-003-0906ND
2016-08-019590-004-0945ND
2016-08-089590-010-0824ND
2017-02-099590-002-0850ND
2017-02-099590-003-0930ND
2017-02-099590-004-1000ND
2017-02-189590-010-1210ND
2017-05-099590-010-0735ND
2017-08-089590-001-0820ND
2017-08-089590-005-1105ND
2017-08-159590-010-1125ND
2017-09-059590-001-0840ND
2017-09-059590-002-0910ND
2017-09-059590-003-0958ND
2017-09-059590-005-1056ND
2017-09-289590-004-0915ND
2017-11-069590-010-1145ND
2018-03-059590-001-0959ND
2018-03-059590-002-1032ND
2018-03-059590-003-1115ND
2018-03-059590-004-1140ND
2018-03-059590-005-1214ND
2018-05-219590-010-1110ND
2018-08-089590-001-0845ND
2018-08-089590-002-0940ND
2018-08-089590-003-1030ND
2018-08-089590-004-1115ND
2018-08-089590-005-1200ND
2018-08-139590-010-1125ND
2018-11-129590-010-1030ND
2019-03-274792-001-0750ND
2019-03-274792-003-0815ND
2019-03-274792-004-0800ND
2019-03-274792-005-0845ND
2019-03-274792-015-1100ND
2019-04-164792-001-1035ND
2019-04-164792-003-1100ND
2019-04-164792-004-1125ND
2019-04-164792-005-1300ND
2019-04-164792-006-0910ND
2019-04-164792-015-1215ND
2019-07-084792-001-0950ND
2019-07-084792-002-1035ND
2019-07-084792-003-1055ND
2019-07-084792-004-1020ND
2019-07-084792-005-1400ND
2019-07-084792-006-1315ND
2019-07-094792-015-0900ND
2019-10-154792-001-0740ND
2019-10-154792-002-1110ND
2019-10-154792-003-1135ND
2019-10-154792-004-1025ND
2019-10-154792-005-1345ND
2019-10-154792-006-0945ND
2019-10-154792-015-0845ND