EWG's Tap Water Database — 2021 UPDATE


Tetrachloroethylene (perchloroethylene)

Parker Little River Water System

Dry cleaning chemical tetrachloroethylene, or perc, can cause cancer. It pollutes soil and groundwater due to emissions from dry cleaning facilities, and automotive, metalworking and other industries. Read More.

The EPA considers tetrachloroethylene a likely human carcinogen. It has been linked with increased incidence of lung, breast and colon cancers. Tetrachloroethylene also damages the liver, kidneys and central nervous system. The California public health goal of 0.06 parts per billion, set to protect against cancer, is 80 times lower than the amount allowed by the federal government, which is a Maximum Contaminant Level of 5 parts per billion.

Click here to read more about carcinogenic VOCs.





Samples exceeding legal limit (MCL)


Samples exceeding
health guidelines

Testing results - average by year

YearAverage resultSamples takenDetectionsRange of results
20140.445 ppb43ND - 0.640 ppb
20150.618 ppb440.560 ppb - 0.730 ppb
20160.930 ppb110.930 ppb
20170.810 ppb110.810 ppb
20181.20 ppb111.20 ppb
20191.10 ppb111.10 ppb

ppb = parts per billion

State and national drinking water standards and health guidelines

EWG Health Guideline 0.06 ppb

The EWG Health Guideline of 0.06 ppb for tetrachloroethylene 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 cancer.

EPA Maximum Contaminant
Level (MCL) 5 ppb

The legal limit for tetrachloroethylene, established in 1991, was based on analytical detection limits at the time that the standard was set. This limit does not fully protect against the risk of cancer due to tetrachloroethylene exposure.

ppb = parts per billion

All test results

Date Lab ID Result
2014-01-09AI262200.610 ppb
2014-04-08AI373230.530 ppb
2014-07-09AI451600.640 ppb
2015-01-23AI633330.570 ppb
2015-04-10AI745970.560 ppb
2015-07-10AI824890.730 ppb
2015-10-12AI926600.610 ppb
2016-02-10AJ062250.930 ppb
2017-05-11AJ552380.810 ppb
2018-02-12AJ836281.20 ppb
2019-03-07AK128891.10 ppb