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EWG's Tap Water Database — 2019 UPDATE

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Total trihalomethanes (TTHMs)

City of Corona

Trihalomethanes are cancer-causing contaminants that form during water treatment with chlorine and other disinfectants. The total trihalomethanes group includes four chemicals: chloroform, bromodichloromethane, dibromochloromethane and bromoform. Read More.

Studies conducted in the U.S. and Europe have found that drinking tap water that carries disinfection byproducts increases the risk of developing bladder cancer. In animal studies, all trihalomethanes cause liver, kidney and intestinal tumors. Some human epidemiological studies also reported an association between disinfection byproducts and an increased risk of problems during pregnancy, including spontaneous miscarriage, cardiovascular defects, neural tube defects and low birth weight.

The health guideline of 0.15 parts per billion, or ppb, for the group of four trihalomethanes, or THM4/TTHM, was defined in a peer-reviewed scientific study by EWG and represents a one-in-one-million lifetime cancer risk level.

Click here to read more about disinfection byproducts.

 

279

Samples

0

Samples exceeding legal limit (MCL)

180

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
201216.7 ppb3931ND - 40.0 ppb
20138.28 ppb7139ND - 42.0 ppb
20147.66 ppb6033ND - 38.0 ppb
20158.74 ppb5531ND - 34.0 ppb
201617.6 ppb2217ND - 38.0 ppb
201717.3 ppb3229ND - 38.0 ppb

ppb = parts per billion

State and national drinking water standards and health guidelines

EWG Health Guideline 0.15 ppb

The health guideline of 0.15 parts per billion, or ppb, for the group of four trihalomethanes, or THM4/TTHM, was defined in a peer-reviewed scientific study by EWG and represents a one-in-one-million lifetime cancer risk level.

EPA Maximum Contaminant
Level (MCL) 80 ppb

The legal limit for the group of four trihalomethanes, established in 1998, was based on the need for residual disinfectant levels in water served to customers and the cost of treatment. This limit does not fully protect against the risk of cancer due to exposure to trihalomethanes.

ppb = parts per billion

All test results

Date Lab ID Result
2012-03-124790-019-134523.0 ppb
2012-03-124790-036-14008.20 ppb
2012-03-124790-041-1445ND
2012-03-124790-043-110015.0 ppb
2012-03-124790-049-102522.0 ppb
2012-06-044790-019-094029.0 ppb
2012-06-044790-036-132525.0 ppb
2012-06-044790-041-1300ND
2012-06-044790-801-100035.0 ppb
2012-06-044790-802-1140ND
2012-06-044790-803-153040.0 ppb
2012-06-044790-804-143037.0 ppb
2012-06-044790-805-14108.30 ppb
2012-06-044790-806-111036.0 ppb
2012-06-044790-807-132536.0 ppb
2012-06-044790-808-110539.0 ppb
2012-06-274790-062-1020ND
2012-09-114790-019-105018.0 ppb
2012-09-114790-036-115516.0 ppb
2012-09-114790-041-1150ND
2012-09-114790-801-105033.0 ppb
2012-09-114790-802-1135ND
2012-09-114790-803-082519.0 ppb
2012-09-114790-804-085522.0 ppb
2012-09-114790-805-080013.0 ppb
2012-09-114790-806-111526.0 ppb
2012-09-114790-807-133016.0 ppb
2012-09-114790-808-103520.0 ppb
2012-12-104790-019-10509.30 ppb
2012-12-104790-036-12009.00 ppb
2012-12-104790-041-1145ND
2012-12-104790-801-091026.0 ppb
2012-12-104790-802-1100ND
2012-12-104790-803-10102.60 ppb
2012-12-104790-804-09006.90 ppb
2012-12-104790-805-094010.00 ppb
2012-12-104790-806-104511.0 ppb
2012-12-104790-807-113027.0 ppb
2012-12-104790-808-140012.0 ppb
2013-02-064790-021-0930ND
2013-02-064790-027-1330ND
2013-02-064790-030-1130ND
2013-02-064790-039-1130ND
2013-02-134790-052-1510ND
2013-02-134790-054-1350ND
2013-02-134790-062-1440ND
2013-03-114790-019-08302.50 ppb
2013-03-114790-036-13453.30 ppb
2013-03-114790-041-1450ND
2013-03-114790-801-112024.0 ppb
2013-03-114790-802-13058.30 ppb
2013-03-114790-803-1615ND
2013-03-114790-804-15202.80 ppb
2013-03-114790-805-16253.10 ppb
2013-03-114790-806-125018.0 ppb
2013-03-114790-807-112019.0 ppb
2013-03-114790-808-092511.0 ppb
2013-05-014790-024-1230ND
2013-05-014790-038-1050ND
2013-05-084790-003-1440ND
2013-05-084790-022-1400ND
2013-05-084790-023-0910ND
2013-05-164790-019-134016.0 ppb
2013-05-164790-034-0915ND
2013-05-164790-043-105023.0 ppb
2013-06-104790-019-151020.0 ppb
2013-06-104790-036-134514.0 ppb
2013-06-104790-041-0920ND
2013-06-104790-801-111542.0 ppb
2013-06-104790-802-12106.20 ppb
2013-06-104790-803-113016.0 ppb
2013-06-104790-804-103018.0 ppb
2013-06-104790-805-11502.00 ppb
2013-06-104790-806-114520.0 ppb
2013-06-104790-807-124021.0 ppb
2013-06-104790-808-122019.0 ppb
2013-06-124790-055-1135ND
2013-06-264790-028-0900ND
2013-08-079590-032-0940ND
2013-08-159590-033-0900ND
2013-08-159590-056-1435ND
2013-08-219590-029-1002ND
2013-08-229590-013-0940ND
2013-08-229590-014-1500ND
2013-08-229590-015-1402ND
2013-08-229590-031-0825ND
2013-09-049590-055-1115ND
2013-09-099590-019-134522.0 ppb
2013-09-099590-036-132515.0 ppb
2013-09-099590-041-1410ND
2013-09-099590-801-123032.0 ppb
2013-09-099590-802-13454.10 ppb
2013-09-099590-803-171015.0 ppb
2013-09-099590-804-165016.0 ppb
2013-09-099590-805-17308.50 ppb
2013-09-099590-806-145020.0 ppb
2013-09-099590-807-090421.0 ppb
2013-09-099590-808-102721.0 ppb
2013-12-109590-055-0845ND
2013-12-169590-019-1430ND
2013-12-169590-036-13002.00 ppb
2013-12-169590-041-1330ND
2013-12-169590-801-104023.0 ppb
2013-12-169590-802-1150ND
2013-12-169590-803-14003.20 ppb
2013-12-169590-804-14503.00 ppb
2013-12-169590-805-14301.90 ppb
2013-12-169590-806-113018.0 ppb
2013-12-169590-807-090028.0 ppb
2013-12-169590-808-094525.0 ppb
2014-02-129590-021-0900ND
2014-02-129590-027-1020ND
2014-02-129590-028-1450ND
2014-02-129590-039-1100ND
2014-02-129590-052-1145ND
2014-02-129590-054-13551.50 ppb
2014-02-269590-030-0730ND
2014-03-039590-019-1345ND
2014-03-039590-036-14306.50 ppb
2014-03-039590-041-1505ND
2014-03-039590-801-131532.0 ppb
2014-03-039590-802-1510ND
2014-03-039590-803-12291.80 ppb
2014-03-039590-804-10262.20 ppb
2014-03-039590-805-13052.00 ppb
2014-03-039590-806-143510.00 ppb
2014-03-039590-807-085538.0 ppb
2014-03-039590-808-11352.30 ppb
2014-03-129590-055-1120ND
2014-05-149590-024-1325ND
2014-05-149590-038-1035ND
2014-05-149590-043-091522.0 ppb
2014-05-159590-019-115516.0 ppb
2014-05-159590-022-0850ND
2014-05-159590-023-1005ND
2014-05-159590-034-1500ND
2014-06-029590-801-120027.0 ppb
2014-06-029590-802-10457.50 ppb
2014-06-029590-803-082514.0 ppb
2014-06-029590-804-085013.0 ppb
2014-06-029590-805-09205.40 ppb
2014-06-029590-806-123016.0 ppb
2014-06-029590-807-095017.0 ppb
2014-06-029590-808-102017.0 ppb
2014-08-139590-015-0930ND
2014-08-139590-031-1455ND
2014-08-139590-032-1100ND
2014-08-139590-033-1315ND
2014-08-219590-029-0900ND
2014-08-269590-003-1400ND
2014-08-279590-014-1315ND
2014-08-279590-056-1415ND
2014-08-289590-013-1030ND
2014-09-159590-801-130031.0 ppb
2014-09-159590-802-140020.0 ppb
2014-09-159590-803-081513.0 ppb
2014-09-159590-804-091015.0 ppb
2014-09-159590-805-09355.80 ppb
2014-09-159590-806-133025.0 ppb
2014-09-159590-807-101025.0 ppb
2014-09-159590-808-113021.0 ppb
2014-09-169590-054-1500ND
2014-12-159590-801-142024.0 ppb
2014-12-159590-802-1340ND
2014-12-159590-803-08500.560 ppb
2014-12-159590-804-09200.770 ppb
2014-12-159590-805-0950ND
2014-12-159590-807-102026.0 ppb
2014-12-159590-808-11350.820 ppb
2014-12-159590-809-10400.510 ppb
2015-02-039590-030-100024.0 ppb
2015-02-129590-027-0900ND
2015-02-129590-028-1420ND
2015-02-129590-030-0810ND
2015-02-129590-039-09500.850 ppb
2015-02-129590-052-13301.60 ppb
2015-03-099590-801-125025.0 ppb
2015-03-099590-802-123012.0 ppb
2015-03-099590-803-09001.40 ppb
2015-03-099590-804-0935ND
2015-03-099590-805-1015ND
2015-03-099590-807-104015.0 ppb
2015-03-099590-808-13205.30 ppb
2015-03-099590-809-111016.0 ppb
2015-05-289590-003-0940ND
2015-05-289590-019-104517.0 ppb
2015-05-289590-024-0930ND
2015-05-289590-034-0830ND
2015-05-289590-038-1000ND
2015-05-289590-043-110026.0 ppb
2015-06-089590-801-145034.0 ppb
2015-06-089590-802-14205.00 ppb
2015-06-089590-803-090012.0 ppb
2015-06-089590-804-094011.0 ppb
2015-06-089590-805-10101.30 ppb
2015-06-089590-807-104024.0 ppb
2015-06-089590-808-134022.0 ppb
2015-06-089590-809-110028.0 ppb
2015-06-099590-062-0815ND
2015-08-129590-029-0900ND
2015-08-129590-031-1020ND
2015-08-129590-032-1100ND
2015-08-129590-056-0940ND
2015-08-209590-013-0900ND
2015-08-209590-014-1430ND
2015-08-209590-015-11300.500 ppb
2015-08-209590-033-0950ND
2015-09-179590-801-112032.0 ppb
2015-09-179590-802-1100ND
2015-09-179590-803-08154.80 ppb
2015-09-179590-804-08402.60 ppb
2015-09-179590-805-09006.60 ppb
2015-09-179590-807-091023.0 ppb
2015-09-179590-808-104015.0 ppb
2015-09-179590-809-102028.0 ppb
2015-10-149590-023-0930ND
2015-10-149590-054-13303.00 ppb
2015-12-239590-801-101530.0 ppb
2015-12-239590-802-1130ND
2015-12-239590-803-0910ND
2015-12-239590-804-0945ND
2015-12-239590-805-0930ND
2015-12-239590-807-151027.0 ppb
2015-12-239590-808-1420ND
2015-12-239590-809-144027.0 ppb
2016-03-099590-801-102524.0 ppb
2016-03-099590-802-1050ND
2016-03-099590-803-1110ND
2016-03-099590-804-0840ND
2016-03-099590-805-0910ND
2016-03-099590-807-133024.0 ppb
2016-03-099590-808-14403.40 ppb
2016-03-099590-809-140024.0 ppb
2016-06-099590-801-115133.0 ppb
2016-06-099590-802-1045ND
2016-06-099590-803-082719.0 ppb
2016-06-099590-804-085219.0 ppb
2016-06-099590-805-091020.0 ppb
2016-06-099590-807-093634.0 ppb
2016-06-099590-808-102826.0 ppb
2016-06-099590-809-100638.0 ppb
2016-09-139590-802-13502.80 ppb
2016-09-139590-808-145036.0 ppb
2016-09-139590-809-144038.0 ppb
2016-12-159590-802-13501.80 ppb
2016-12-159590-808-101022.0 ppb
2016-12-159590-809-095023.0 ppb
2017-03-169590-801-090032.0 ppb
2017-03-169590-802-0950ND
2017-03-169590-803-11207.90 ppb
2017-03-169590-804-10307.20 ppb
2017-03-169590-805-11002.50 ppb
2017-03-169590-807-152033.0 ppb
2017-03-169590-808-142033.0 ppb
2017-03-169590-809-144034.0 ppb
2017-06-159590-801-112022.0 ppb
2017-06-159590-802-1540ND
2017-06-159590-803-092015.0 ppb
2017-06-159590-804-094517.0 ppb
2017-06-159590-805-101013.0 ppb
2017-06-159590-807-134013.0 ppb
2017-06-159590-808-143017.0 ppb
2017-06-159590-809-140013.0 ppb
2017-09-139590-801-110038.0 ppb
2017-09-139590-802-14008.30 ppb
2017-09-139590-803-085022.0 ppb
2017-09-139590-804-091028.0 ppb
2017-09-139590-805-093023.0 ppb
2017-09-139590-807-100018.0 ppb
2017-09-139590-808-144024.0 ppb
2017-09-139590-809-152018.0 ppb
2017-12-149590-801-135030.0 ppb
2017-12-149590-802-1450ND
2017-12-149590-803-083011.0 ppb
2017-12-149590-804-08558.60 ppb
2017-12-149590-805-092512.0 ppb
2017-12-149590-807-094517.0 ppb
2017-12-149590-808-102019.0 ppb
2017-12-149590-809-101018.0 ppb