EWG's Tap Water Database — 2021 UPDATE



Green Meadows Subdivision

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.





Samples exceeding legal limit (MCL)


Samples exceeding
health guidelines

Testing results - average by year

YearAverage resultSamples takenDetectionsRange of results
20150.500 ppb110.500 ppb
20160.650 ppb440.500 ppb - 0.900 ppb
20170.850 ppb440.600 ppb - 1.000 ppb
20180.300 ppb21ND - 0.600 ppb
20191.20 ppb220.700 ppb - 1.70 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
2015-11-09VA010-DCLS0.500 ppb
2016-03-02E1601028900.500 ppb
2016-07-25E1606081680.900 ppb
2016-07-25E1606081670.700 ppb
2016-12-12E1612005580.500 ppb
2017-02-15E1612018800.800 ppb
2017-05-24E1703028181.000 ppb
2017-08-15E1706003651.000 ppb
2017-12-05E1708054980.600 ppb
2018-01-29E1712056740.600 ppb
2019-07-22E1906064501.70 ppb
2019-07-22E1906064510.700 ppb