Menu

EWG's Tap Water Database — 2021 UPDATE

Donate

Perchlorate

Rancho California Water District

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

 

237

Samples

0

Samples exceeding legal limit (MCL)

0

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
2014ND430ND
2015ND430ND
2016ND220ND
2017ND560ND
2018ND480ND
2019ND250ND

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
2014-01-164790-090-1039ND
2014-01-284790-059-0930ND
2014-04-024790-084-1000ND
2014-04-024790-085-1030ND
2014-04-034790-043-1015ND
2014-04-094790-042-1122ND
2014-04-164790-059-1040ND
2014-05-014790-012-0928ND
2014-05-084790-044-0900ND
2014-05-084790-084-1045ND
2014-05-084790-085-1115ND
2014-05-084790-086-1130ND
2014-05-084790-090-1050ND
2014-05-154790-019-0830ND
2014-05-154790-036-1030ND
2014-05-154790-051-1000ND
2014-05-204790-043-0900ND
2014-05-214790-027-1000ND
2014-05-214790-047-0845ND
2014-05-234790-038-0920ND
2014-05-234790-041-0800ND
2014-05-234790-095-1000ND
2014-05-284790-143-0930ND
2014-06-034790-025-0855ND
2014-06-034790-035-0140ND
2014-06-034790-048-1055ND
2014-07-104790-024-0840ND
2014-07-104790-059-1045ND
2014-07-164790-017-1030ND
2014-07-294790-065-0845ND
2014-08-054790-097-0950ND
2014-08-064790-143-0905ND
2014-08-074790-040-1010ND
2014-08-074790-095-0905ND
2014-09-034790-037-0958ND
2014-09-044790-059-0935ND
2014-10-014790-012-0924ND
2014-10-024790-029-0940ND
2014-10-024790-041-1018ND
2014-10-024790-059-0900ND
2014-10-084790-065-0830ND
2014-10-094790-047-1000ND
2014-12-094790-019-1000ND
2015-01-074790-065-1115ND
2015-01-134790-059-0915ND
2015-01-294790-142-1030ND
2015-02-204790-034-0945ND
2015-03-054790-028-0932ND
2015-03-104790-012-1058ND
2015-03-114790-048-1048ND
2015-04-084790-046-0858ND
2015-04-084790-065-0910ND
2015-04-144790-059-0920ND
2015-04-164790-017-1030ND
2015-04-214790-018-0930ND
2015-04-224790-053-1200ND
2015-04-224790-142-1015ND
2015-05-064790-084-1115ND
2015-05-064790-085-1130ND
2015-05-064790-086-1145ND
2015-05-064790-090-1200ND
2015-05-064790-143-1050ND
2015-05-144790-024-0900ND
2015-05-144790-097-1145ND
2015-06-024790-045-1202ND
2015-06-024790-051-1122ND
2015-07-024790-065-0900ND
2015-07-074790-015-1000ND
2015-07-074790-059-0845ND
2015-07-144790-142-0000ND
2015-07-144790-142-1000ND
2015-08-044790-031-1002ND
2015-08-054790-012-1041ND
2015-08-054790-143-1135ND
2015-08-074790-027-0840ND
2015-09-094790-053-0810ND
2015-09-094790-058-1017ND
2015-09-104790-071-1113ND
2015-10-064790-065-1045ND
2015-10-064790-065-1500ND
2015-10-084790-059-0930ND
2015-10-144790-142-1045ND
2015-11-044790-035-1240ND
2015-11-044790-143-0955ND
2015-12-094790-038-0955ND
2015-12-094790-046-0925ND
2016-01-124790-059-0940ND
2016-01-124790-065-1035ND
2016-01-134790-044-0900ND
2016-01-204790-142-1030ND
2016-03-154790-037-1200ND
2016-04-144790-142-1100ND
2016-04-214790-059-1045ND
2016-04-224790-065-0915ND
2016-05-054790-084-1420ND
2016-05-054790-086-1410ND
2016-05-054790-090-1400ND
2016-05-114790-036-1230ND
2016-07-064790-031-1115ND
2016-07-134790-059-0945ND
2016-07-134790-065-1015ND
2016-07-194790-085-0930ND
2016-07-254790-012-1230ND
2016-07-274790-142-1130ND
2016-10-044790-065-1120ND
2016-10-054790-059-1200ND
2016-11-094790-153-1110ND
2016-11-164790-012-1034ND
2017-01-044790-065-0950ND
2017-01-184790-090-1120ND
2017-01-264790-059-0930ND
2017-02-034790-153-1050ND
2017-03-234790-142-1055ND
2017-04-034790-012-1004ND
2017-04-114790-042-1045ND
2017-04-114790-043-1000ND
2017-04-114790-084-0940ND
2017-04-114790-085-1040ND
2017-04-124790-142-1030ND
2017-04-194790-059-0950ND
2017-04-194790-065-1035ND
2017-04-274790-086-1025ND
2017-05-034790-015-0930ND
2017-05-034790-019-1020ND
2017-05-034790-036-1105ND
2017-05-034790-044-0950ND
2017-05-034790-046-0941ND
2017-05-034790-047-1052ND
2017-05-034790-051-1130ND
2017-05-044790-038-1450ND
2017-05-044790-084-1115ND
2017-05-044790-085-1045ND
2017-05-044790-090-1055ND
2017-05-044790-095-1215ND
2017-05-044790-153-1010ND
2017-05-104790-018-1110ND
2017-05-104790-041-0955ND
2017-05-104790-043-1040ND
2017-05-144790-027-0830ND
2017-05-144790-029-0930ND
2017-05-144790-086-1115ND
2017-06-074790-025-0920ND
2017-06-084790-035-1100ND
2017-06-154790-048-1053ND
2017-07-114790-017-1055ND
2017-07-114790-024-0945ND
2017-07-114790-059-1033ND
2017-07-114790-065-0950ND
2017-07-134790-142-1035ND
2017-07-264790-045-0850ND
2017-08-044790-040-0845ND
2017-08-094790-095-1000ND
2017-08-094790-097-1123ND
2017-08-104790-153-1215ND
2017-09-014790-150-0930ND
2017-09-284790-059-0943ND
2017-10-044790-065-0935ND
2017-10-104790-059-1031ND
2017-10-114790-041-1107ND
2017-10-174790-029-1101ND
2017-11-084790-150-1445ND
2017-11-224790-151-1100ND
2017-11-294790-012-0935ND
2017-12-134790-019-1038ND
2018-01-044790-142-1242ND
2018-01-124790-065-1156ND
2018-01-174790-059-0957ND
2018-01-264790-037-1000ND
2018-02-074790-034-0923ND
2018-02-074790-150-1242ND
2018-02-074790-151-1148ND
2018-03-074790-035-1050ND
2018-03-154790-018-1125ND
2018-03-154790-048-1057ND
2018-04-114790-059-1140ND
2018-04-134790-017-1000ND
2018-04-134790-053-1205ND
2018-04-254790-152-1135ND
2018-05-034790-051-1020ND
2018-05-034790-150-1130ND
2018-05-034790-151-1235ND
2018-05-044790-086-1030ND
2018-05-044790-090-1020ND
2018-05-084790-084-0912ND
2018-05-154790-024-0942ND
2018-05-184790-097-0918ND
2018-05-234790-047-1004ND
2018-05-244790-012-1038ND
2018-06-064790-065-0957ND
2018-06-074790-045-1100ND
2018-07-024790-012-1036ND
2018-07-104790-065-1115ND
2018-07-114790-059-0950ND
2018-07-174790-152-1045ND
2018-07-184790-015-0901ND
2018-08-084790-085-0945ND
2018-08-094790-031-1128ND
2018-08-094790-151-1000ND
2018-08-144790-150-0914ND
2018-08-154790-027-1029ND
2018-09-114790-071-0855ND
2018-09-134790-051-1035ND
2018-10-034790-152-1030ND
2018-10-054790-059-0755ND
2018-10-164790-065-0900ND
2018-10-174790-155-1240ND
2018-11-064790-150-0957ND
2018-11-064790-151-1116ND
2018-11-274790-143-0946ND
2018-12-144790-012-0910ND
2018-12-144790-038-0815ND
2018-12-174790-046-1210ND
2019-01-084790-059-1110ND
2019-01-094790-152-1100ND
2019-01-094790-155-0930ND
2019-01-144790-065-0835ND
2019-02-124790-153-1201ND
2019-02-194790-150-0958ND
2019-02-194790-151-0841ND
2019-03-264790-037-0950ND
2019-04-024790-059-1011ND
2019-04-024790-155-1115ND
2019-04-044790-065-0927ND
2019-05-014790-036-1015ND
2019-05-074790-012-0831ND
2019-05-084790-084-1006ND
2019-05-084790-085-1016ND
2019-05-084790-086-1027ND
2019-05-084790-090-1101ND
2019-05-154790-044-0955ND
2019-07-014790-031-1052ND
2019-07-104790-059-0900ND
2019-07-104790-065-1015ND
2019-07-224790-155-0820ND
2019-10-034790-012-1040ND
2019-10-044790-065-0905ND
2019-10-094790-059-0901ND