EWG's Tap Water Database — 2021 UPDATE



Carson, City of

Pentachlorophenol is a carcinogenic chemical used as a wood preservative. It harms developing fetuses, and causes immune suppression and hormone disruption.





Samples exceeding legal limit (MCL)


Samples exceeding
health guidelines

Testing results - average by year

YearAverage resultSamples takenDetectionsRange of results

ppb = parts per billion

State and national drinking water standards and health guidelines

EWG Health Guideline 0.3 ppb

The EWG Health Guideline of 0.3 ppb for pentachlorophenol 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) 1 ppb

The legal limit for pentachlorophenol, established in 1991, was based on analytical detection limits at the time that the standard was set.

ppb = parts per billion

All test results

Date Lab ID Result