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EWG's Tap Water Database — 2021 UPDATE

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Perchlorate

Calif State Polytechnical Univ - Pomona

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

 

543

Samples

0

Samples exceeding legal limit (MCL)

192

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
20145.22 ppb119ND - 10.00 ppb
20150.377 ppb786ND - 6.50 ppb
20160.819 ppb588ND - 7.30 ppb
20172.85 ppb10247ND - 8.50 ppb
20182.89 ppb15365ND - 9.10 ppb
20192.78 ppb14157ND - 10.00 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
2014-01-074790-004-1135ND
2014-01-074790-005-11255.30 ppb
2014-02-044790-005-11207.80 ppb
2014-03-044790-005-11155.90 ppb
2014-04-014790-005-102510.00 ppb
2014-05-064790-005-11256.80 ppb
2014-06-034790-005-10355.10 ppb
2014-07-014790-005-10405.90 ppb
2014-08-054790-005-0950ND
2014-09-024790-005-10406.30 ppb
2014-12-304790-005-10454.30 ppb
2015-03-174790-005-1220ND
2015-04-074790-005-10554.30 ppb
2015-04-144790-011-1125ND
2015-04-144790-011-1130ND
2015-04-214790-011-1130ND
2015-04-214790-011-1135ND
2015-04-294790-011-1240ND
2015-05-054790-005-10356.50 ppb
2015-05-054790-011-1135ND
2015-05-054790-011-1145ND
2015-05-154790-011-1000ND
2015-05-194790-011-11404.30 ppb
2015-05-194790-011-1145ND
2015-05-264790-011-1200ND
2015-05-264790-011-1205ND
2015-06-024790-005-1005ND
2015-06-024790-011-1135ND
2015-06-024790-011-1140ND
2015-06-124790-011-0930ND
2015-06-164790-011-1110ND
2015-06-164790-011-11154.10 ppb
2015-06-234790-011-1110ND
2015-06-234790-011-1115ND
2015-06-304790-011-1110ND
2015-06-304790-011-1115ND
2015-07-074790-005-10354.30 ppb
2015-07-074790-011-1150ND
2015-07-074790-011-1155ND
2015-07-144790-011-1055ND
2015-07-144790-011-1100ND
2015-07-214790-011-1105ND
2015-07-214790-011-1110ND
2015-07-284790-011-1045ND
2015-07-284790-011-1050ND
2015-08-044790-011-1010ND
2015-08-044790-011-1015ND
2015-08-114790-011-1125ND
2015-08-114790-011-1130ND
2015-08-184790-011-1020ND
2015-08-184790-011-1030ND
2015-08-254790-011-0955ND
2015-08-254790-011-1000ND
2015-09-014790-011-1110ND
2015-09-014790-011-1115ND
2015-09-084790-011-1005ND
2015-09-084790-011-1010ND
2015-09-154790-011-1035ND
2015-09-224790-011-1000ND
2015-09-224790-011-1005ND
2015-09-294790-011-1040ND
2015-09-294790-011-1045ND
2015-10-064790-011-0950ND
2015-10-064790-011-0955ND
2015-10-134790-011-1200ND
2015-10-134790-011-1210ND
2015-10-204790-011-1150ND
2015-10-204790-011-1200ND
2015-10-274790-011-1148ND
2015-10-274790-011-1150ND
2015-11-034790-011-1015ND
2015-11-034790-011-1020ND
2015-11-104790-011-1100ND
2015-11-104790-011-1105ND
2015-11-174790-011-1025ND
2015-11-174790-011-1030ND
2015-11-244790-011-0945ND
2015-11-244790-011-0950ND
2015-12-014790-011-1005ND
2015-12-014790-011-1010ND
2015-12-084790-005-11555.90 ppb
2015-12-094790-011-0845ND
2015-12-094790-011-0900ND
2015-12-154790-011-1145ND
2015-12-154790-011-1150ND
2015-12-224790-011-0940ND
2015-12-224790-011-0945ND
2015-12-294790-011-0950ND
2015-12-294790-011-0955ND
2016-01-054790-011-1010ND
2016-01-054790-011-1015ND
2016-01-124790-011-1000ND
2016-01-124790-011-1005ND
2016-01-194790-011-10307.30 ppb
2016-01-264790-011-1015ND
2016-01-264790-011-1020ND
2016-02-024790-011-1025ND
2016-03-224790-011-1220ND
2016-03-304790-011-1020ND
2016-03-304790-011-1030ND
2016-04-124790-011-1110ND
2016-04-194790-011-1040ND
2016-04-264790-011-1055ND
2016-05-034790-005-11306.00 ppb
2016-05-034790-011-1155ND
2016-05-104790-011-1135ND
2016-05-174790-011-1115ND
2016-05-244790-011-1150ND
2016-05-314790-011-1115ND
2016-06-074790-005-11105.40 ppb
2016-06-074790-011-1125ND
2016-06-144790-011-1115ND
2016-06-214790-011-1130ND
2016-06-284790-011-1115ND
2016-07-054790-005-11006.40 ppb
2016-07-054790-011-1110ND
2016-07-124790-011-1030ND
2016-07-284790-011-0715ND
2016-07-284790-011-0720ND
2016-08-094790-011-1030ND
2016-08-164790-011-1150ND
2016-08-234790-011-1145ND
2016-08-304790-011-1125ND
2016-09-064790-005-11205.20 ppb
2016-09-064790-011-1130ND
2016-09-144790-011-1230ND
2016-09-144790-011-1240ND
2016-09-204790-011-1145ND
2016-09-274790-011-1135ND
2016-09-274790-011-1155ND
2016-10-044790-005-10105.30 ppb
2016-10-044790-011-1130ND
2016-10-114790-011-1120ND
2016-10-184790-011-1100ND
2016-10-254790-011-1100ND
2016-11-014790-005-10055.60 ppb
2016-11-014790-011-1125ND
2016-11-084790-011-1120ND
2016-11-154790-011-0930ND
2016-11-224790-011-1113ND
2016-11-224790-011-1115ND
2016-11-294790-011-1057ND
2016-11-294790-011-1100ND
2016-12-064790-011-1120ND
2016-12-134790-011-1110ND
2016-12-204790-005-12006.30 ppb
2016-12-204790-011-1120ND
2017-01-034790-005-10107.30 ppb
2017-01-034790-011-1120ND
2017-01-104790-011-1120ND
2017-01-174790-011-1110ND
2017-01-314790-011-1110ND
2017-02-074790-005-10005.70 ppb
2017-02-074790-011-1120ND
2017-02-144790-011-1120ND
2017-02-214790-011-1120ND
2017-02-284790-011-1110ND
2017-03-074790-011-1130ND
2017-03-144790-005-11005.50 ppb
2017-03-144790-011-1220ND
2017-03-214790-011-1130ND
2017-03-284790-011-1120ND
2017-04-044790-005-09454.50 ppb
2017-04-114790-011-1200ND
2017-04-114790-014-11206.80 ppb
2017-04-144790-011-1000ND
2017-04-184790-014-11456.60 ppb
2017-04-254790-011-1100ND
2017-04-254790-014-10205.80 ppb
2017-04-284790-011-0945ND
2017-05-104790-011-1115ND
2017-05-104790-014-11008.20 ppb
2017-05-194790-011-0930ND
2017-05-234790-011-1130ND
2017-05-234790-014-11107.60 ppb
2017-06-024790-011-1130ND
2017-06-064790-005-09507.20 ppb
2017-06-064790-011-1120ND
2017-06-064790-014-11307.40 ppb
2017-06-094790-011-1130ND
2017-06-204790-011-1205ND
2017-06-204790-014-11256.90 ppb
2017-06-234790-011-1325ND
2017-06-274790-011-1120ND
2017-06-274790-014-11408.30 ppb
2017-06-304790-011-0930ND
2017-07-054790-005-09258.20 ppb
2017-07-054790-011-1045ND
2017-07-054790-014-11157.00 ppb
2017-07-074790-011-1111ND
2017-07-114790-011-1035ND
2017-07-114790-014-11006.70 ppb
2017-07-144790-011-0950ND
2017-07-184790-011-1035ND
2017-07-184790-014-10506.70 ppb
2017-07-214790-011-1015ND
2017-08-014790-005-09405.00 ppb
2017-08-014790-011-1050ND
2017-08-014790-014-11105.70 ppb
2017-08-044790-011-1030ND
2017-08-084790-011-1105ND
2017-08-084790-014-11204.30 ppb
2017-08-154790-011-1020ND
2017-08-154790-014-10404.20 ppb
2017-08-184790-011-1010ND
2017-08-224790-011-1100ND
2017-08-224790-014-11206.00 ppb
2017-08-254790-011-1020ND
2017-08-294790-011-1120ND
2017-08-294790-014-11305.10 ppb
2017-09-014790-011-1045ND
2017-09-054790-005-09407.20 ppb
2017-09-054790-011-1100ND
2017-09-054790-014-11107.20 ppb
2017-09-084790-011-1000ND
2017-09-194790-011-1115ND
2017-09-194790-014-12108.50 ppb
2017-09-264790-011-09353.30 ppb
2017-09-264790-014-09457.60 ppb
2017-10-034790-005-09306.50 ppb
2017-10-034790-011-1110ND
2017-10-034790-014-11305.40 ppb
2017-10-064790-011-0950ND
2017-10-104790-011-10503.20 ppb
2017-10-104790-014-09106.20 ppb
2017-10-174790-011-11302.90 ppb
2017-10-174790-014-12506.80 ppb
2017-10-204790-011-1000ND
2017-10-274790-011-1105ND
2017-11-074790-005-09357.80 ppb
2017-11-074790-011-1110ND
2017-11-074790-014-11207.60 ppb
2017-11-144790-011-1120ND
2017-11-144790-014-11407.70 ppb
2017-11-214790-011-15503.20 ppb
2017-11-214790-014-15157.20 ppb
2017-11-284790-011-10503.00 ppb
2017-11-284790-014-11007.20 ppb
2017-12-054790-005-09307.90 ppb
2017-12-054790-011-1100ND
2017-12-054790-014-11106.60 ppb
2017-12-084790-011-11004.30 ppb
2017-12-124790-011-1140ND
2017-12-124790-014-11505.90 ppb
2017-12-194790-011-10503.10 ppb
2017-12-194790-014-11108.20 ppb
2017-12-214790-011-1200ND
2017-12-264790-011-0945ND
2017-12-264790-014-1020ND
2018-01-024790-011-1040ND
2018-01-024790-014-11157.60 ppb
2018-01-054790-011-1130ND
2018-01-094790-011-1200ND
2018-01-094790-014-12356.70 ppb
2018-01-124790-011-1045ND
2018-01-164790-011-1045ND
2018-01-164790-014-11106.50 ppb
2018-01-194790-011-1100ND
2018-01-234790-011-1020ND
2018-01-234790-014-11107.10 ppb
2018-01-314790-011-1210ND
2018-01-314790-014-11407.40 ppb
2018-02-024790-011-1200ND
2018-02-064790-005-10208.30 ppb
2018-02-064790-014-12057.70 ppb
2018-02-094790-011-1110ND
2018-02-134790-005-11407.30 ppb
2018-02-134790-011-1100ND
2018-02-134790-014-11207.70 ppb
2018-02-164790-011-1040ND
2018-02-204790-011-1035ND
2018-02-204790-014-11007.60 ppb
2018-02-234790-011-1030ND
2018-02-274790-011-1122ND
2018-02-274790-014-10306.70 ppb
2018-03-014790-011-1000ND
2018-03-064790-005-09408.00 ppb
2018-03-064790-011-1100ND
2018-03-064790-014-11205.20 ppb
2018-03-094790-011-1000ND
2018-03-134790-011-10204.10 ppb
2018-03-134790-014-10407.00 ppb
2018-03-204790-011-1100ND
2018-03-204790-014-11305.90 ppb
2018-03-274790-011-1045ND
2018-03-274790-014-11114.70 ppb
2018-03-294790-011-1030ND
2018-04-034790-005-11306.70 ppb
2018-04-034790-011-1030ND
2018-04-034790-014-11107.80 ppb
2018-04-064790-011-1115ND
2018-04-104790-011-1106ND
2018-04-104790-014-10406.40 ppb
2018-04-174790-011-1110ND
2018-04-174790-014-11508.70 ppb
2018-04-204790-011-1500ND
2018-04-244790-011-1100ND
2018-04-244790-014-11585.00 ppb
2018-04-274790-011-10454.30 ppb
2018-05-014790-005-09404.50 ppb
2018-05-014790-011-1100ND
2018-05-014790-014-11105.20 ppb
2018-05-044790-011-1030ND
2018-05-084790-011-1100ND
2018-05-084790-014-11247.60 ppb
2018-05-114790-011-1100ND
2018-05-154790-011-1100ND
2018-05-154790-014-11259.10 ppb
2018-05-184790-011-1110ND
2018-05-224790-011-1140ND
2018-05-224790-014-12028.80 ppb
2018-05-254790-011-1030ND
2018-05-294790-011-1100ND
2018-05-294790-014-11306.90 ppb
2018-06-014790-011-1045ND
2018-06-054790-005-10007.40 ppb
2018-06-054790-011-1130ND
2018-06-054790-014-11557.30 ppb
2018-06-084790-011-11004.00 ppb
2018-06-124790-011-1000ND
2018-06-124790-014-11366.50 ppb
2018-06-154790-011-1030ND
2018-06-194790-011-1135ND
2018-06-194790-014-12408.60 ppb
2018-06-264790-011-1215ND
2018-06-264790-014-12368.00 ppb
2018-07-034790-005-09557.30 ppb
2018-07-034790-011-1120ND
2018-07-034790-014-12008.50 ppb
2018-07-064790-011-10454.60 ppb
2018-07-104790-011-1310ND
2018-07-104790-014-13286.60 ppb
2018-07-134790-011-1045ND
2018-07-174790-011-1200ND
2018-07-174790-014-12267.40 ppb
2018-07-204790-011-1015ND
2018-07-244790-011-1215ND
2018-07-244790-014-12467.40 ppb
2018-07-274790-011-1030ND
2018-07-314790-011-1245ND
2018-07-314790-014-13196.80 ppb
2018-08-074790-005-10106.80 ppb
2018-08-074790-011-1205ND
2018-08-074790-014-13157.50 ppb
2018-08-104790-011-1000ND
2018-08-144790-011-1045ND
2018-08-144790-014-11107.50 ppb
2018-08-174790-011-1130ND
2018-08-214790-011-1140ND
2018-08-214790-014-11508.10 ppb
2018-08-244790-011-1000ND
2018-08-284790-011-1130ND
2018-08-284790-014-11457.40 ppb
2018-08-314790-011-1030ND
2018-09-044790-005-11308.40 ppb
2018-09-044790-011-1250ND
2018-09-044790-014-13258.00 ppb
2018-09-074790-011-1120ND
2018-09-114790-011-0800ND
2018-09-144790-011-1015ND
2018-09-184790-011-1215ND
2018-09-184790-014-12458.60 ppb
2018-09-214790-011-1315ND
2018-09-254790-011-1114ND
2018-09-254790-014-11386.80 ppb
2018-09-284790-011-1010ND
2018-10-024790-005-11556.20 ppb
2018-10-024790-011-1330ND
2018-10-024790-014-14005.80 ppb
2018-10-054790-011-1015ND
2018-10-094790-011-1310ND
2018-10-094790-014-13345.40 ppb
2018-10-124790-011-1045ND
2018-10-164790-011-1120ND
2018-10-164790-014-11454.50 ppb
2018-10-194790-011-1012ND
2018-10-234790-011-1240ND
2018-10-234790-014-13087.50 ppb
2018-10-264790-011-1045ND
2018-10-304790-011-1330ND
2018-10-304790-014-13586.10 ppb
2018-11-024790-011-1045ND
2018-11-064790-005-11306.60 ppb
2018-11-164790-011-1030ND
2018-11-204790-011-1205ND
2018-11-204790-014-12406.10 ppb
2018-11-274790-011-0800ND
2018-11-274790-011-1248ND
2018-11-274790-014-11546.20 ppb
2018-11-304790-011-1115ND
2018-12-044790-005-12456.40 ppb
2018-12-044790-005-12506.50 ppb
2018-12-044790-011-1210ND
2018-12-044790-014-14086.30 ppb
2018-12-074790-011-1120ND
2018-12-114790-011-1050ND
2018-12-114790-014-11206.30 ppb
2018-12-184790-011-1135ND
2018-12-184790-014-10405.60 ppb
2018-12-214790-011-1500ND
2018-12-264790-011-1005ND
2018-12-264790-014-0953ND
2019-01-024790-005-11506.80 ppb
2019-01-024790-011-1325ND
2019-01-024790-014-14156.70 ppb
2019-01-044790-011-1030ND
2019-01-084790-011-1100ND
2019-01-084790-014-10126.60 ppb
2019-01-154790-011-1215ND
2019-01-154790-014-12407.50 ppb
2019-01-184790-011-1200ND
2019-01-224790-011-1350ND
2019-01-224790-014-14126.50 ppb
2019-01-254790-011-1030ND
2019-01-294790-011-1055ND
2019-01-294790-014-09567.00 ppb
2019-02-014790-011-1030ND
2019-02-054790-005-11556.80 ppb
2019-02-054790-011-1310ND
2019-02-054790-014-13527.10 ppb
2019-02-084790-011-1130ND
2019-02-124790-011-1125ND
2019-02-124790-014-11527.00 ppb
2019-02-154790-011-1100ND
2019-02-194790-011-1230ND
2019-02-194790-014-12547.40 ppb
2019-02-224790-011-1100ND
2019-02-264790-011-1225ND
2019-02-264790-014-12486.90 ppb
2019-03-054790-005-12507.50 ppb
2019-03-054790-011-1420ND
2019-03-054790-014-15007.10 ppb
2019-03-124790-011-1240ND
2019-03-124790-014-13545.80 ppb
2019-03-194790-011-1315ND
2019-03-194790-014-13466.10 ppb
2019-03-224790-011-1255ND
2019-03-264790-011-1224ND
2019-03-264790-014-11305.90 ppb
2019-03-294790-011-1030ND
2019-04-024790-005-11356.20 ppb
2019-04-024790-011-1305ND
2019-04-024790-014-13406.10 ppb
2019-04-054790-011-1030ND
2019-04-094790-011-1125ND
2019-04-094790-014-11505.80 ppb
2019-04-124790-011-1030ND
2019-04-164790-011-1200ND
2019-04-164790-014-12245.80 ppb
2019-04-194790-011-1042ND
2019-04-234790-011-1105ND
2019-04-234790-014-11324.90 ppb
2019-04-304790-011-1135ND
2019-04-304790-014-12006.20 ppb
2019-05-074790-011-1345ND
2019-05-074790-014-14205.40 ppb
2019-05-104790-011-1030ND
2019-05-144790-011-1115ND
2019-05-144790-014-11454.60 ppb
2019-05-174790-011-1100ND
2019-05-244790-011-1100ND
2019-05-284790-011-1110ND
2019-05-284790-014-11304.40 ppb
2019-06-044790-005-10104.50 ppb
2019-06-044790-011-1135ND
2019-06-044790-014-12244.60 ppb
2019-06-114790-011-1025ND
2019-06-114790-014-10487.30 ppb
2019-06-144790-011-1030ND
2019-06-184790-011-1120ND
2019-06-184790-014-11505.20 ppb
2019-06-254790-011-0940ND
2019-06-254790-014-10025.80 ppb
2019-06-284790-011-1040ND
2019-07-024790-005-10206.60 ppb
2019-07-024790-011-1135ND
2019-07-024790-014-12126.40 ppb
2019-07-034790-011-1020ND
2019-07-094790-011-1050ND
2019-07-094790-014-11386.30 ppb
2019-07-124790-011-1045ND
2019-07-164790-011-1200ND
2019-07-164790-014-12266.40 ppb
2019-07-194790-011-1030ND
2019-07-234790-011-1200ND
2019-07-234790-014-12197.50 ppb
2019-07-264790-011-1045ND
2019-07-304790-011-1040ND
2019-07-304790-014-105810.00 ppb
2019-08-024790-011-1110ND
2019-08-064790-005-13187.50 ppb
2019-08-064790-011-1254ND
2019-08-064790-014-11307.10 ppb
2019-08-134790-011-1250ND
2019-08-134790-014-13107.70 ppb
2019-08-164790-011-1045ND
2019-08-204790-011-1255ND
2019-08-204790-014-13307.70 ppb
2019-08-234790-011-1040ND
2019-08-274790-011-1310ND
2019-08-274790-014-12157.40 ppb
2019-08-304790-011-0940ND
2019-09-034790-005-11358.40 ppb
2019-09-034790-011-1300ND
2019-09-034790-014-12107.40 ppb
2019-09-064790-011-1300ND
2019-09-104790-011-1253ND
2019-09-104790-014-11587.80 ppb
2019-09-134790-011-1040ND
2019-09-204790-011-1430ND
2019-09-244790-011-1155ND
2019-09-244790-014-12208.40 ppb
2019-09-274790-011-0930ND
2019-10-014790-005-09257.20 ppb
2019-10-014790-011-1050ND
2019-10-014790-014-11367.70 ppb
2019-10-084790-011-1142ND
2019-10-084790-014-12328.40 ppb
2019-10-114790-011-1045ND
2019-10-154790-011-1135ND
2019-10-154790-014-11568.70 ppb
2019-10-184790-011-0930ND
2019-10-224790-011-1250ND
2019-10-224790-014-13167.30 ppb
2019-10-294790-011-1110ND
2019-10-294790-014-11347.20 ppb
2019-11-014790-011-1050ND
2019-11-054790-005-09457.10 ppb
2019-11-054790-011-1050ND
2019-11-054790-014-11247.50 ppb
2019-11-084790-011-1130ND
2019-11-224790-011-1050ND
2019-11-274790-011-1100ND
2019-12-034790-005-11207.30 ppb
2019-12-034790-011-1240ND
2019-12-034790-014-13229.20 ppb
2019-12-064790-011-1220ND
2019-12-104790-011-1200ND
2019-12-104790-014-12227.20 ppb
2019-12-114790-011-0950ND
2019-12-174790-005-11009.20 ppb
2019-12-174790-011-1255ND
2019-12-174790-014-1320ND