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EWG's Tap Water Database — 2021 UPDATE

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Perchlorate

Suburban Water Systems - San Jose Hills

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

 

205

Samples

0

Samples exceeding legal limit (MCL)

27

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
2013N/A00N/A
2014ND380ND
2015ND220ND
20160.114 ppb351ND - 4.00 ppb
20170.747 ppb539ND - 5.50 ppb
20180.932 ppb378ND - 4.80 ppb
20191.96 ppb209ND - 5.20 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
2014-01-139588-065-1036ND
2014-01-139588-075-1045ND
2014-02-119588-065-1041ND
2014-02-119588-075-1101ND
2014-02-219588-071-1322ND
2014-03-119588-071-1349ND
2014-03-129588-065-1323ND
2014-03-129588-075-1337ND
2014-04-159588-065-1125ND
2014-04-159588-071-1101ND
2014-04-159588-075-1350ND
2014-05-069588-071-1559ND
2014-05-069588-075-1610ND
2014-05-139588-065-1015ND
2014-05-139588-071-0937ND
2014-05-139588-075-1031ND
2014-06-099588-065-1006ND
2014-06-099588-071-0934ND
2014-06-099588-075-1026ND
2014-07-109588-065-1000ND
2014-07-109588-075-1015ND
2014-07-159588-071-1227ND
2014-08-119588-065-0928ND
2014-08-119588-071-0846ND
2014-08-119588-075-0944ND
2014-09-109588-071-1245ND
2014-09-179588-065-0957ND
2014-09-179588-075-1017ND
2014-10-159588-065-0953ND
2014-10-159588-075-1004ND
2014-10-179588-071-1030ND
2014-10-299588-071-1551ND
2014-11-219588-065-1021ND
2014-11-219588-071-0950ND
2014-11-219588-075-1032ND
2014-12-159588-065-1012ND
2014-12-159588-071-0940ND
2014-12-159588-075-1030ND
2015-01-199588-071-1125ND
2015-02-209588-071-1038ND
2015-03-109588-071-1030ND
2015-04-159588-071-1338ND
2015-05-019588-075-1043ND
2015-05-049588-075-1033ND
2015-05-119588-071-0925ND
2015-06-159588-071-1055ND
2015-06-209588-075-2216ND
2015-06-239588-075-1550ND
2015-07-019588-065-0954ND
2015-07-069588-075-0932ND
2015-07-159588-065-1351ND
2015-07-159588-071-1338ND
2015-07-159588-075-1405ND
2015-08-129588-065-0942ND
2015-08-129588-071-0920ND
2015-08-129588-075-0953ND
2015-09-109588-065-1132ND
2015-09-109588-075-1153ND
2015-09-119588-071-0925ND
2015-10-129588-071-1010ND
2016-01-129588-071-0942ND
2016-02-089588-075-1045ND
2016-02-179588-065-1216ND
2016-02-179588-071-1145ND
2016-03-019588-065-1100ND
2016-03-019588-071-1038ND
2016-03-019588-075-1120ND
2016-03-269588-065-0700ND
2016-03-269588-075-0653ND
2016-04-069588-065-1341ND
2016-04-069588-071-1320ND
2016-04-069588-075-1403ND
2016-05-029588-065-1058ND
2016-05-029588-071-1001ND
2016-05-029588-075-1108ND
2016-06-279588-065-1040ND
2016-06-279588-071-0950ND
2016-06-279588-075-1057ND
2016-07-199588-065-0940ND
2016-07-199588-075-1218ND
2016-08-169588-065-1430ND
2016-08-169588-071-1520ND
2016-08-169588-075-1545ND
2016-09-199588-065-1140ND
2016-09-199588-075-1240ND
2016-10-109588-071-1628ND
2016-10-119588-065-0854ND
2016-10-119588-075-0908ND
2016-11-049588-065-1150ND
2016-11-049588-071-1135ND
2016-11-049588-075-1248ND
2016-12-139588-065-1135ND
2016-12-139588-071-1055ND
2016-12-149588-075-0710ND
2016-12-289588-075-16354.00 ppb
2017-01-039588-065-1044ND
2017-01-039588-075-11054.20 ppb
2017-01-099588-065-1030ND
2017-01-099588-075-1050ND
2017-01-129588-065-08354.10 ppb
2017-01-129588-075-0846ND
2017-01-139588-065-1310ND
2017-01-139588-075-13305.50 ppb
2017-01-169588-065-0845ND
2017-01-169588-075-0908ND
2017-02-089588-070-0840ND
2017-02-209588-065-1125ND
2017-02-209588-075-1136ND
2017-03-079588-071-0943ND
2017-03-079588-075-1020ND
2017-03-089588-065-0945ND
2017-03-179588-065-1410ND
2017-03-179588-075-13594.00 ppb
2017-04-119588-065-1013ND
2017-04-119588-071-1002ND
2017-04-119588-075-1032ND
2017-04-243761-065-0918ND
2017-04-249588-065-0918ND
2017-05-039588-065-1125ND
2017-05-039588-071-1102ND
2017-05-039588-075-1150ND
2017-06-099588-065-0851ND
2017-06-099588-071-0842ND
2017-06-099588-075-09114.40 ppb
2017-07-119588-065-1112ND
2017-07-119588-071-1033ND
2017-07-119588-075-1135ND
2017-08-119588-065-0932ND
2017-08-119588-071-0903ND
2017-08-119588-075-0943ND
2017-09-119588-065-1150ND
2017-09-119588-071-1034ND
2017-09-119588-075-1205ND
2017-10-099588-071-1452ND
2017-10-103761-071-1135ND
2017-10-109588-071-1135ND
2017-10-119588-071-1439ND
2017-10-129588-071-1350ND
2017-10-139588-071-1400ND
2017-10-179588-065-09564.10 ppb
2017-10-179588-071-0852ND
2017-10-179588-075-10304.70 ppb
2017-11-179588-065-0845ND
2017-11-179588-071-0822ND
2017-11-179588-075-09104.10 ppb
2017-12-159588-065-1334ND
2017-12-159588-071-1325ND
2017-12-159588-075-13424.50 ppb
2018-01-179588-065-0901ND
2018-01-179588-071-0841ND
2018-01-179588-075-09124.10 ppb
2018-02-069588-065-1030ND
2018-02-069588-071-1018ND
2018-02-069588-075-10424.10 ppb
2018-03-079588-065-0858ND
2018-03-079588-075-0910ND
2018-03-129588-071-0915ND
2018-03-209588-075-0945ND
2018-03-269588-075-0905ND
2018-04-119588-065-0933ND
2018-04-119588-075-0955ND
2018-05-039588-065-1110ND
2018-05-039588-071-1035ND
2018-05-039588-075-1121ND
2018-06-019588-071-1020ND
2018-06-049588-065-0848ND
2018-06-049588-075-0900ND
2018-07-069588-065-0912ND
2018-07-069588-071-0906ND
2018-07-069588-075-0938ND
2018-08-069588-065-0856ND
2018-08-069588-075-0914ND
2018-08-079588-071-0913ND
2018-09-219588-065-0842ND
2018-09-219588-075-09034.20 ppb
2018-09-269588-071-1018ND
2018-10-029588-065-09084.00 ppb
2018-10-029588-075-09584.30 ppb
2018-10-039588-071-0855ND
2018-11-069588-065-09354.20 ppb
2018-11-069588-071-0858ND
2018-11-069588-075-12384.80 ppb
2018-12-049588-071-0843ND
2018-12-049588-075-09084.80 ppb
2018-12-129588-065-1345ND
2019-01-119588-065-1020ND
2019-01-119588-075-10454.50 ppb
2019-02-089588-065-0805ND
2019-02-089588-075-09204.00 ppb
2019-03-049588-065-1330ND
2019-03-119588-075-1215ND
2019-04-089588-065-10284.10 ppb
2019-04-089588-075-10455.00 ppb
2019-05-079588-065-0853ND
2019-05-079588-075-09054.00 ppb
2019-06-109588-075-1035ND
2019-07-109588-065-10114.40 ppb
2019-07-109588-075-10255.20 ppb
2019-08-089588-065-12494.00 ppb
2019-09-129588-065-09414.00 ppb
2019-10-099588-065-1215ND
2019-10-099588-071-1200ND
2019-11-209588-065-1045ND
2019-12-129588-065-1010ND
2019-12-129588-071-1031ND