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EWG's Tap Water Database — 2021 UPDATE

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Perchlorate

Valley Water Company

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

 

299

Samples

0

Samples exceeding legal limit (MCL)

37

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
20140.943 ppb4710ND - 4.80 ppb
20151.26 ppb5616ND - 5.00 ppb
20160.440 ppb485ND - 4.40 ppb
2017ND430ND
20180.469 ppb586ND - 5.20 ppb
2019ND470ND

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
2014-05-059590-006-1030ND
2014-05-079590-002-1010ND
2014-05-079590-003-10304.10 ppb
2014-05-079590-004-09104.50 ppb
2014-05-079590-005-09404.20 ppb
2014-05-129590-006-1020ND
2014-05-199590-006-0745ND
2014-05-279590-006-0830ND
2014-06-029590-006-0730ND
2014-06-049590-002-1015ND
2014-06-049590-003-09154.40 ppb
2014-06-049590-004-09204.70 ppb
2014-06-049590-005-0950ND
2014-06-099590-006-0800ND
2014-06-169590-006-0800ND
2014-06-239590-006-0730ND
2014-07-029590-002-0900ND
2014-07-029590-003-09204.40 ppb
2014-07-029590-004-09404.80 ppb
2014-07-029590-005-1015ND
2014-07-029590-006-0850ND
2014-07-079590-006-0830ND
2014-07-149590-006-0745ND
2014-07-219590-006-0830ND
2014-07-289590-006-0830ND
2014-08-049590-006-0900ND
2014-08-059590-002-0750ND
2014-08-059590-003-0845ND
2014-08-059590-004-1020ND
2014-08-059590-005-0930ND
2014-08-119590-006-0730ND
2014-08-189590-006-0815ND
2014-08-259590-006-0900ND
2014-09-029590-006-0900ND
2014-09-039590-002-08104.10 ppb
2014-09-039590-003-08304.40 ppb
2014-09-039590-004-09304.70 ppb
2014-09-039590-005-1030ND
2014-09-099590-006-0800ND
2014-09-159590-006-0745ND
2014-09-229590-006-0830ND
2014-09-299590-006-0745ND
2014-10-069590-006-0730ND
2014-10-079590-003-0915ND
2014-10-139590-006-0730ND
2014-10-209590-006-0800ND
2014-10-279590-006-0900ND
2015-04-069590-002-11455.00 ppb
2015-04-069590-006-1125ND
2015-04-139590-006-0900ND
2015-04-209590-006-0800ND
2015-04-279590-006-0825ND
2015-05-049590-006-0800ND
2015-05-079590-002-10204.50 ppb
2015-05-089590-006-1445ND
2015-05-119590-006-0815ND
2015-05-189590-006-0920ND
2015-05-269590-006-0840ND
2015-06-019590-002-11004.30 ppb
2015-06-019590-003-10204.40 ppb
2015-06-019590-004-09254.80 ppb
2015-06-019590-005-10504.70 ppb
2015-06-019590-006-1125ND
2015-06-049590-006-1345ND
2015-06-089590-006-1120ND
2015-06-159590-006-0815ND
2015-06-229590-006-0800ND
2015-06-299590-006-0815ND
2015-07-019590-002-1015ND
2015-07-019590-004-09504.30 ppb
2015-07-019590-005-0930ND
2015-07-069590-006-1130ND
2015-07-139590-006-0730ND
2015-07-209590-006-0740ND
2015-07-279590-006-0845ND
2015-08-039590-006-1040ND
2015-08-049590-002-09104.20 ppb
2015-08-049590-003-1115ND
2015-08-049590-004-0950ND
2015-08-049590-005-0930ND
2015-08-109590-006-1045ND
2015-08-179590-006-0800ND
2015-08-249590-006-0740ND
2015-08-319590-006-0815ND
2015-08-319590-008-08304.40 ppb
2015-09-029590-002-08454.50 ppb
2015-09-029590-003-1000ND
2015-09-029590-004-09254.40 ppb
2015-09-029590-005-08154.20 ppb
2015-09-089590-006-0800ND
2015-09-109590-006-1330ND
2015-09-149590-006-0810ND
2015-09-219590-006-1125ND
2015-09-289590-006-0810ND
2015-10-059590-002-09454.10 ppb
2015-10-059590-003-08504.20 ppb
2015-10-059590-006-0825ND
2015-10-129590-006-1050ND
2015-10-199590-006-0830ND
2015-10-269590-006-0810ND
2015-11-029590-002-09154.30 ppb
2015-11-029590-003-09304.50 ppb
2015-11-029590-006-0955ND
2016-03-019590-003-0810ND
2016-03-019590-006-0800ND
2016-04-049590-005-1215ND
2016-04-049590-006-1230ND
2016-04-119590-006-0800ND
2016-04-189590-006-0750ND
2016-04-259590-006-0825ND
2016-05-029590-006-0800ND
2016-05-049590-005-0815ND
2016-05-099590-006-0930ND
2016-05-139590-002-0930ND
2016-05-139590-003-1030ND
2016-05-139590-004-1005ND
2016-05-169590-006-0845ND
2016-05-179590-006-1105ND
2016-05-239590-006-0800ND
2016-06-019590-002-1020ND
2016-06-019590-003-0840ND
2016-06-019590-004-0925ND
2016-06-019590-005-0955ND
2016-06-019590-006-0820ND
2016-07-019590-002-0920ND
2016-07-019590-003-0910ND
2016-07-019590-004-09554.10 ppb
2016-07-019590-005-10254.40 ppb
2016-07-059590-006-0830ND
2016-07-119590-006-0815ND
2016-07-189590-006-0850ND
2016-07-259590-006-0815ND
2016-08-019590-006-0910ND
2016-08-039590-002-0840ND
2016-08-039590-003-0850ND
2016-08-039590-004-0930ND
2016-08-039590-005-1010ND
2016-08-089590-006-0815ND
2016-08-159590-006-0800ND
2016-08-229590-006-0840ND
2016-08-299590-006-0820ND
2016-10-039590-006-0815ND
2016-10-049590-002-0845ND
2016-10-049590-003-0945ND
2016-10-109590-006-0830ND
2016-10-189590-006-0815ND
2016-10-259590-006-0835ND
2016-11-089590-002-09504.10 ppb
2016-11-089590-003-0920ND
2016-11-089590-004-08504.20 ppb
2016-11-089590-005-10204.30 ppb
2017-05-029590-002-1320ND
2017-05-029590-003-1135ND
2017-05-029590-004-1110ND
2017-05-029590-005-1355ND
2017-05-159590-006-0940ND
2017-05-199590-006-1230ND
2017-05-229590-006-0830ND
2017-05-309590-006-0815ND
2017-07-059590-006-0900ND
2017-07-109590-006-0855ND
2017-07-119590-002-0915ND
2017-07-119590-003-0925ND
2017-07-119590-005-1010ND
2017-07-139590-004-1145ND
2017-07-189590-006-0845ND
2017-07-249590-006-0800ND
2017-08-019590-006-0900ND
2017-08-029590-002-0940ND
2017-08-029590-003-0955ND
2017-08-029590-004-1015ND
2017-08-029590-005-1040ND
2017-08-079590-006-0815ND
2017-08-149590-006-0820ND
2017-08-219590-006-0855ND
2017-08-289590-006-0815ND
2017-09-059590-006-0815ND
2017-09-069590-002-0845ND
2017-09-069590-003-0900ND
2017-09-069590-004-0930ND
2017-09-069590-005-0955ND
2017-09-119590-006-1000ND
2017-09-189590-006-0800ND
2017-09-259590-006-0800ND
2017-10-029590-006-0815ND
2017-10-039590-002-0745ND
2017-10-039590-003-0800ND
2017-10-099590-006-0840ND
2017-10-169590-006-0810ND
2017-10-239590-006-0845ND
2017-10-309590-006-1010ND
2017-11-029590-002-0845ND
2017-11-029590-003-0855ND
2017-11-029590-006-0920ND
2018-03-129590-002-1005ND
2018-03-129590-003-1050ND
2018-03-129590-006-1355ND
2018-03-199590-006-0900ND
2018-03-269590-006-1120ND
2018-05-029590-002-0905ND
2018-05-029590-003-1030ND
2018-05-029590-004-09454.40 ppb
2018-05-029590-005-10154.80 ppb
2018-05-039590-006-0745ND
2018-05-079590-006-0750ND
2018-05-149590-006-0900ND
2018-05-229590-006-0905ND
2018-05-299590-006-1450ND
2018-06-049590-006-0800ND
2018-06-059590-002-0815ND
2018-06-059590-003-0830ND
2018-06-059590-004-0935ND
2018-06-059590-005-1010ND
2018-06-119590-006-0800ND
2018-06-189590-006-0850ND
2018-06-259590-006-0800ND
2018-07-029590-006-0800ND
2018-07-039590-002-0815ND
2018-07-039590-003-0830ND
2018-07-039590-004-0930ND
2018-07-039590-005-1000ND
2018-07-099590-006-0835ND
2018-07-169590-006-0825ND
2018-07-239590-006-0800ND
2018-07-309590-006-0830ND
2018-08-019590-002-0920ND
2018-08-019590-003-0950ND
2018-08-019590-004-1000ND
2018-08-019590-005-1020ND
2018-08-069590-006-0815ND
2018-08-139590-006-0800ND
2018-08-209590-006-0745ND
2018-08-279590-006-0730ND
2018-09-049590-002-0930ND
2018-09-049590-003-09104.00 ppb
2018-09-049590-006-0800ND
2018-09-109590-006-0730ND
2018-09-179590-006-0800ND
2018-09-249590-006-0800ND
2018-10-019590-006-1100ND
2018-10-039590-002-1010ND
2018-10-039590-003-10204.20 ppb
2018-10-039590-004-11055.20 ppb
2018-10-039590-005-1130ND
2018-10-089590-006-0815ND
2018-10-179590-006-0800ND
2018-10-229590-006-0800ND
2018-10-299590-006-0830ND
2018-11-059590-006-0800ND
2018-11-069590-002-07454.60 ppb
2018-11-069590-003-0850ND
2018-11-129590-006-0800ND
2019-05-069590-006-1250ND
2019-05-079590-002-0810ND
2019-05-079590-003-0815ND
2019-05-079590-004-0940ND
2019-05-079590-005-1010ND
2019-05-139590-006-0755ND
2019-05-209590-006-0800ND
2019-05-289590-006-0815ND
2019-06-039590-006-0840ND
2019-06-049590-002-0830ND
2019-06-049590-003-0845ND
2019-06-049590-004-0940ND
2019-06-049590-005-1010ND
2019-06-109590-006-0800ND
2019-06-179590-006-0815ND
2019-06-249590-006-0835ND
2019-07-019590-006-0800ND
2019-07-029590-002-0815ND
2019-07-029590-003-0830ND
2019-07-029590-004-0945ND
2019-07-089590-006-0745ND
2019-07-159590-006-0845ND
2019-07-229590-006-0800ND
2019-07-299590-006-0820ND
2019-08-059590-006-0900ND
2019-08-069590-002-0840ND
2019-08-069590-003-0850ND
2019-08-069590-004-0930ND
2019-08-129590-006-0850ND
2019-08-199590-006-0855ND
2019-08-269590-006-0820ND
2019-09-039590-002-0920ND
2019-09-039590-003-0930ND
2019-09-039590-004-1150ND
2019-09-039590-005-1130ND
2019-09-039590-006-0800ND
2019-09-099590-006-0912ND
2019-09-169590-006-0810ND
2019-09-239590-006-0840ND
2019-10-019590-006-0810ND
2019-10-029590-002-1035ND
2019-10-029590-003-1010ND
2019-10-029590-005-0915ND
2019-10-079590-006-0850ND
2019-10-149590-006-0815ND
2019-10-219590-006-0815ND
2019-10-289590-006-0840ND