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EWG's Tap Water Database — 2021 UPDATE

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Perchlorate

City of Davis

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

 

83

Samples

0

Samples exceeding legal limit (MCL)

0

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
2014ND180ND
2015ND160ND
2016ND170ND
2017ND120ND
2018ND110ND
2019ND90ND

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
2014-08-055810-052-0935ND
2014-08-055810-002-0822ND
2014-08-055810-004-0810ND
2014-08-055810-006-0837ND
2014-08-055810-009-1120ND
2014-08-055810-010-0918ND
2014-08-055810-014-0950ND
2014-08-055810-015-1036ND
2014-08-055810-016-0853ND
2014-08-055810-017-0909ND
2014-08-055810-018-0753ND
2014-08-055810-019-0737ND
2014-08-055810-020-0657ND
2014-08-055810-023-0720ND
2014-08-055810-024-1025ND
2014-08-055810-025-1000ND
2014-08-055810-026-1014ND
2014-08-055810-030-1059ND
2015-07-075810-004-1253ND
2015-07-075810-052-0648ND
2015-07-075810-030-0919ND
2015-07-075810-026-1041ND
2015-07-075810-025-0832ND
2015-07-075810-024-1120ND
2015-07-075810-023-0904ND
2015-07-075810-020-0757ND
2015-07-075810-002-1333ND
2015-07-075810-018-0721ND
2015-07-075810-017-1030ND
2015-07-075810-016-0957ND
2015-07-075810-015-1321ND
2015-07-075810-010-1148ND
2015-07-075810-006-1115ND
2015-07-215810-009-0747ND
2016-01-265810-019-1005ND
2016-07-135810-009-0935ND
2016-07-135810-010-0919ND
2016-07-135810-006-0747ND
2016-07-135810-015-0825ND
2016-07-134790-016-0704ND
2016-07-135810-004-0753ND
2016-07-135810-017-0912ND
2016-07-135810-020-0640ND
2016-07-135810-018-0620ND
2016-07-135810-030-0844ND
2016-07-135810-024-0808ND
2016-07-135810-019-0630ND
2016-07-135810-025-0857ND
2016-07-135810-023-0656ND
2016-07-205810-026-0757ND
2016-07-205810-052-0843ND
2017-03-205810-057-1120ND
2017-06-145810-057-0820ND
2017-08-025810-025-0925ND
2017-08-025810-018-0843ND
2017-08-025810-026-0943ND
2017-08-025810-052-1115ND
2017-08-025810-006-0859ND
2017-08-025810-020-0805ND
2017-08-025810-019-0823ND
2017-08-035810-030-0625ND
2017-09-205810-057-0910ND
2017-12-125810-057-0735ND
2018-02-145810-057-0925ND
2018-04-185810-028-0855ND
2018-08-155810-057-0840ND
2018-08-155810-019-0902ND
2018-08-155810-052-0930ND
2018-08-155810-025-0755ND
2018-08-155810-018-0819ND
2018-08-155810-030-0640ND
2018-08-155810-028-0720ND
2018-08-155810-020-1001ND
2018-11-075810-028-0818ND
2019-02-065810-028-0820ND
2019-08-079590-057-1200ND
2019-08-079590-025-1102ND
2019-08-079590-052-1134ND
2019-08-079590-030-1008ND
2019-08-079590-028-1033ND
2019-08-089590-020-1103ND
2019-08-089590-018-1010ND
2019-08-089590-019-1033ND