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EWG's Tap Water Database — 2021 UPDATE

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Perchlorate

California Water Service (CWS) - Visalia

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

 

124

Samples

0

Samples exceeding legal limit (MCL)

1

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
2014ND150ND
2015ND210ND
2016ND220ND
2017ND170ND
2018ND220ND
20190.196 ppb271ND - 5.30 ppb

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
2014-01-119588-023-1502ND
2014-01-219588-017-1215ND
2014-04-029588-018-0805ND
2014-04-149588-024-1250ND
2014-05-109588-054-0830ND
2014-06-109588-099-1145ND
2014-07-079588-065-0855ND
2014-07-149588-066-1537ND
2014-09-159588-070-0830ND
2014-09-169588-182-0905ND
2014-09-229588-060-0955ND
2014-09-229588-069-1225ND
2014-10-139588-022-0941ND
2014-10-149588-014-1515ND
2014-11-059588-076-1400ND
2015-01-179588-027-1240ND
2015-01-189588-003-1258ND
2015-01-189588-015-1357ND
2015-02-049588-016-1425ND
2015-02-049588-029-1320ND
2015-02-049588-031-1005ND
2015-02-049588-044-1245ND
2015-02-049588-156-0945ND
2015-04-149588-030-1305ND
2015-04-149588-091-0910ND
2015-05-119588-177-0945ND
2015-05-129588-045-1105ND
2015-06-129588-090-0805ND
2015-07-149588-026-0800ND
2015-07-149588-179-1330ND
2015-08-099588-040-0955ND
2015-08-099588-094-0850ND
2015-09-109588-089-1030ND
2015-09-109588-093-1000ND
2015-09-109588-098-1100ND
2015-11-049588-035-0750ND
2016-02-099588-057-0840ND
2016-03-109588-028-1005ND
2016-03-109588-036-1230ND
2016-03-109588-061-1325ND
2016-03-109588-159-1210ND
2016-03-149588-059-1130ND
2016-04-079588-067-1230ND
2016-05-059588-046-1045ND
2016-05-059588-055-1019ND
2016-05-099588-012-1235ND
2016-05-099588-081-1345ND
2016-06-279588-056-1215ND
2016-06-279588-058-1030ND
2016-07-139588-010-0822ND
2016-07-139588-154-1330ND
2016-07-139588-158-1240ND
2016-08-099588-048-0955ND
2016-08-099588-053-0925ND
2016-09-089588-080-1110ND
2016-09-089588-092-1040ND
2016-09-089588-166-1000ND
2016-11-069588-178-1120ND
2017-01-099588-017-1120ND
2017-01-179588-023-0900ND
2017-04-119588-018-1205ND
2017-04-119588-024-0905ND
2017-05-229588-043-0850ND
2017-05-229588-054-1115ND
2017-07-109588-066-1215ND
2017-07-139588-065-1050ND
2017-08-179588-014-0800ND
2017-09-129588-064-1120ND
2017-09-139588-182-0915ND
2017-09-189588-070-0805ND
2017-09-219588-060-1230ND
2017-09-219588-069-1330ND
2017-10-269588-022-1225ND
2017-12-179588-167-0915ND
2017-12-199588-037-0945ND
2018-01-239588-015-1320ND
2018-02-069588-044-1255ND
2018-02-089588-029-1000ND
2018-02-089588-031-1110ND
2018-03-199588-028-1335ND
2018-04-199588-030-1500ND
2018-04-199588-091-1300ND
2018-05-089588-045-1130ND
2018-05-089588-156-0900ND
2018-05-179588-047-1007ND
2018-05-319588-027-1005ND
2018-05-319588-047-1020ND
2018-06-119588-090-1215ND
2018-07-179588-026-0915ND
2018-07-179588-179-1020ND
2018-08-099588-040-0920ND
2018-08-099588-094-1045ND
2018-08-219590-089-1235ND
2018-09-139588-093-0830ND
2018-09-139588-098-0855ND
2018-11-119588-035-1040ND
2018-12-289588-087-0955ND
2019-02-149588-167-0910ND
2019-02-219588-057-1240ND
2019-03-189588-159-1020ND
2019-03-219588-036-1105ND
2019-03-219588-059-1035ND
2019-03-219588-061-0850ND
2019-04-229588-067-08155.30 ppb
2019-05-139588-081-1120ND
2019-05-169588-046-1050ND
2019-05-169588-055-1000ND
2019-05-209588-067-1312ND
2019-06-129588-056-1100ND
2019-06-129588-058-0950ND
2019-07-179588-010-0711ND
2019-07-179588-016-1144ND
2019-07-179588-154-1030ND
2019-07-179588-154-1033ND
2019-07-179588-158-0929ND
2019-08-209588-016-1120ND
2019-08-249588-047-0731ND
2019-08-259588-048-1040ND
2019-08-259588-053-1010ND
2019-09-139588-092-1127ND
2019-09-139588-166-1035ND
2019-09-179588-080-1145ND
2019-10-179588-003-1201ND
2019-11-209588-178-1515ND