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EWG's Tap Water Database — 2021 UPDATE

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Chloroform

City of Watsonville

Chloroform, one of the total trihalomethanes (TTHMs), is formed when chlorine or other disinfectants are used to treat drinking water. Chloroform and other disinfection byproducts increase the risk of cancer and may cause problems during pregnancy. Read More.

In addition to tap water disinfection, chloroform pollution in the environment also comes from industrial discharges from pulp and paper mills, and from urban wastewater effluent. Human studies show that chloroform damages the kidneys, liver and central nervous system. In animals, chloroform causes infertility, birth defects and cancer.

Click here to read more about disinfection byproducts.

MORE ABOUT THIS CONTAMINANT

 

221

Samples

0

Samples exceeding legal limit (MCL)

112

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
20140.270 ppb479ND - 2.30 ppb
20150.775 ppb3215ND - 2.20 ppb
20163.07 ppb3220ND - 19.0 ppb
20179.75 ppb4622ND - 39.0 ppb
20188.12 ppb3224ND - 26.0 ppb
20199.78 ppb3222ND - 31.0 ppb

ppb = parts per billion

State and national drinking water standards and health guidelines

EWG Health Guideline 0.4 ppb

The EWG Health Guideline of 0.4 ppb for chloroform was proposed in 2018 by the California Office of Environmental Health Hazard Assessment as a one-in-a-million lifetime risk of cancer. Values greater than one-in-a-million cancer risk level can result in increased cancer cases above one in a million people.

ppb = parts per billion

All test results

Date Lab ID Result
2014-02-199590-009-1430ND
2014-02-199590-801-13101.10 ppb
2014-02-199590-802-1030ND
2014-02-199590-803-0945ND
2014-02-199590-804-1145ND
2014-02-199590-805-0850ND
2014-02-199590-806-1345ND
2014-02-199590-807-1125ND
2014-02-199590-808-0915ND
2014-03-199590-004-0800ND
2014-03-199590-005-0745ND
2014-03-199590-006-0800ND
2014-03-199590-007-0840ND
2014-03-199590-009-1100ND
2014-03-199590-010-0915ND
2014-03-199590-011-1000ND
2014-03-199590-012-0920ND
2014-03-199590-013-0835ND
2014-03-199590-014-0740ND
2014-03-199590-015-0805ND
2014-03-199590-016-0900ND
2014-03-199590-029-0845ND
2014-03-199590-030-0900ND
2014-05-219590-801-10001.20 ppb
2014-05-219590-802-09151.40 ppb
2014-05-219590-803-0845ND
2014-05-219590-804-0945ND
2014-05-219590-805-0809ND
2014-05-219590-806-10201.10 ppb
2014-05-219590-807-0930ND
2014-05-219590-808-0828ND
2014-08-139590-801-11101.40 ppb
2014-08-139590-802-09501.10 ppb
2014-08-139590-803-0920ND
2014-08-139590-804-10401.70 ppb
2014-08-139590-805-0815ND
2014-08-139590-806-1145ND
2014-08-139590-807-10202.30 ppb
2014-08-139590-808-0845ND
2014-11-129590-801-1145ND
2014-11-129590-802-10001.40 ppb
2014-11-129590-803-0940ND
2014-11-129590-804-1045ND
2014-11-129590-805-0900ND
2014-11-129590-806-1215ND
2014-11-129590-807-1025ND
2014-11-129590-808-0920ND
2015-02-099590-801-11501.60 ppb
2015-02-099590-802-10351.40 ppb
2015-02-099590-803-1010ND
2015-02-099590-804-11201.80 ppb
2015-02-099590-805-0920ND
2015-02-099590-806-1210ND
2015-02-099590-807-11002.10 ppb
2015-02-099590-808-0945ND
2015-05-139590-801-11101.30 ppb
2015-05-139590-802-10002.00 ppb
2015-05-139590-803-0930ND
2015-05-139590-804-10202.20 ppb
2015-05-139590-805-0830ND
2015-05-139590-806-11351.20 ppb
2015-05-139590-807-10502.20 ppb
2015-05-139590-808-0900ND
2015-08-129590-801-1130ND
2015-08-129590-802-10151.10 ppb
2015-08-129590-803-09451.50 ppb
2015-08-129590-804-1100ND
2015-08-129590-805-0855ND
2015-08-129590-806-13001.30 ppb
2015-08-129590-807-1040ND
2015-08-129590-808-0930ND
2015-11-099590-801-12502.10 ppb
2015-11-099590-802-11301.80 ppb
2015-11-099590-803-1100ND
2015-11-099590-804-1230ND
2015-11-099590-805-1005ND
2015-11-099590-806-1310ND
2015-11-099590-807-12001.20 ppb
2015-11-099590-808-1035ND
2016-02-109590-801-1150ND
2016-02-109590-802-10451.60 ppb
2016-02-109590-803-1010ND
2016-02-109590-804-11301.50 ppb
2016-02-109590-805-0900ND
2016-02-109590-806-1215ND
2016-02-109590-807-11101.60 ppb
2016-02-109590-808-0930ND
2016-05-239590-801-1130ND
2016-05-239590-802-10301.70 ppb
2016-05-239590-803-09301.50 ppb
2016-05-239590-804-11051.000 ppb
2016-05-239590-805-0845ND
2016-05-239590-806-11551.10 ppb
2016-05-239590-807-10501.10 ppb
2016-05-239590-808-0905ND
2016-08-179590-801-13002.60 ppb
2016-08-179590-802-113019.0 ppb
2016-08-179590-803-10309.20 ppb
2016-08-179590-804-133016.0 ppb
2016-08-179590-805-0915ND
2016-08-179590-806-135012.0 ppb
2016-08-179590-807-123016.0 ppb
2016-08-179590-808-10003.60 ppb
2016-11-099590-801-12302.60 ppb
2016-11-099590-802-10152.10 ppb
2016-11-099590-803-09501.30 ppb
2016-11-099590-804-12001.40 ppb
2016-11-099590-805-0905ND
2016-11-099590-806-12501.30 ppb
2016-11-099590-807-1050ND
2016-11-099590-808-0930ND
2017-02-279590-801-12151.10 ppb
2017-02-279590-802-10151.50 ppb
2017-02-279590-803-0945ND
2017-02-279590-804-11151.20 ppb
2017-02-279590-805-0845ND
2017-02-279590-806-1235ND
2017-02-279590-807-10451.20 ppb
2017-02-279590-808-0915ND
2017-03-159590-004-1040ND
2017-03-159590-005-0905ND
2017-03-159590-006-0910ND
2017-03-159590-007-1100ND
2017-03-159590-009-1030ND
2017-03-159590-010-0955ND
2017-03-159590-011-1010ND
2017-03-159590-012-0935ND
2017-03-159590-013-0945ND
2017-03-159590-014-0825ND
2017-03-159590-015-1010ND
2017-03-159590-016-0840ND
2017-03-159590-029-0830ND
2017-03-159590-030-1100ND
2017-05-319590-801-1130ND
2017-05-319590-802-10251.50 ppb
2017-05-319590-803-10001.30 ppb
2017-05-319590-804-1110ND
2017-05-319590-805-0900ND
2017-05-319590-806-11501.50 ppb
2017-05-319590-807-1050ND
2017-05-319590-808-09351.20 ppb
2017-08-169590-801-125524.0 ppb
2017-08-169590-802-115022.0 ppb
2017-08-169590-803-104030.0 ppb
2017-08-169590-804-122039.0 ppb
2017-08-169590-805-0950ND
2017-08-169590-806-133038.0 ppb
2017-08-169590-807-124037.0 ppb
2017-08-169590-808-102013.0 ppb
2017-11-149590-801-120028.0 ppb
2017-11-149590-802-103537.0 ppb
2017-11-149590-803-101038.0 ppb
2017-11-149590-804-111038.0 ppb
2017-11-149590-805-0920ND
2017-11-149590-806-123037.0 ppb
2017-11-149590-807-113038.0 ppb
2017-11-149590-808-095019.0 ppb
2018-02-149590-801-13001.10 ppb
2018-02-149590-802-12001.50 ppb
2018-02-149590-803-11401.10 ppb
2018-02-149590-804-12401.50 ppb
2018-02-149590-805-1100ND
2018-02-149590-806-1315ND
2018-02-149590-807-12201.60 ppb
2018-02-149590-808-11201.30 ppb
2018-05-099590-801-14101.20 ppb
2018-05-099590-802-13101.40 ppb
2018-05-099590-803-12401.20 ppb
2018-05-099590-804-1350ND
2018-05-099590-805-1200ND
2018-05-099590-806-14401.10 ppb
2018-05-099590-807-1330ND
2018-05-099590-808-1220ND
2018-08-229590-801-101017.0 ppb
2018-08-229590-802-104023.0 ppb
2018-08-229590-803-111020.0 ppb
2018-08-229590-804-092025.0 ppb
2018-08-229590-805-1200ND
2018-08-229590-806-083024.0 ppb
2018-08-229590-807-094526.0 ppb
2018-08-229590-808-11303.70 ppb
2018-11-139590-801-121015.0 ppb
2018-11-139590-802-104520.0 ppb
2018-11-139590-803-101515.0 ppb
2018-11-139590-804-110019.0 ppb
2018-11-139590-805-0930ND
2018-11-139590-806-123014.0 ppb
2018-11-139590-807-113019.0 ppb
2018-11-139590-808-10006.00 ppb
2019-02-209590-801-1100ND
2019-02-209590-802-09551.30 ppb
2019-02-209590-803-09351.30 ppb
2019-02-209590-804-10401.20 ppb
2019-02-209590-805-0825ND
2019-02-209590-806-1125ND
2019-02-209590-807-10201.40 ppb
2019-02-209590-808-0915ND
2019-05-089590-801-1000ND
2019-05-089590-802-09001.10 ppb
2019-05-089590-803-08451.10 ppb
2019-05-089590-804-09401.10 ppb
2019-05-089590-805-0800ND
2019-05-089590-806-1030ND
2019-05-089590-807-09201.30 ppb
2019-05-089590-808-0820ND
2019-08-149590-801-123016.0 ppb
2019-08-149590-802-111020.0 ppb
2019-08-149590-803-104028.0 ppb
2019-08-149590-804-121029.0 ppb
2019-08-149590-805-0945ND
2019-08-149590-806-125022.0 ppb
2019-08-149590-807-115028.0 ppb
2019-08-149590-808-10103.20 ppb
2019-11-139590-801-103022.0 ppb
2019-11-139590-802-091531.0 ppb
2019-11-139590-803-085017.0 ppb
2019-11-139590-804-101530.0 ppb
2019-11-139590-805-0815ND
2019-11-139590-806-105025.0 ppb
2019-11-139590-807-100030.0 ppb
2019-11-139590-808-08351.90 ppb