EWG's Tap Water Database — 2021 UPDATE


Polychlorinated biphenyls (PCBs)

Coloma Waterworks

PCBs are synthetic chemicals banned in the U.S. since the 1970s because of their toxicity. PCBs contaminate water by leaching from landfills and hazardous waste clean-up sites. PCBs increase the risk of cancer. Read More.

Up until the late 1970s, PCBs were used widely as coolants and lubricants in transformers, capacitors and other electrical equipment. Currently, PCBs are widely detected in the general population. They build up and are stored in fatty tissues and fluids such as breast milk, and can be passed on to fetuses and infants during pregnancy and breast-feeding. In human epidemiological studies, PCBs have been associated with an elevated risk of breast and prostate cancers. Infants and children with higher PCB exposures during development score lower on measures of neurological function, ranging from decreased IQ scores to� reduced hearing sensitivity. PCBs also affect hormones and damage the immune system.





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 0.09 ppb

The EWG Health Guideline of 0.09 ppb for PCBs 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) 0.5 ppb

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

ppb = parts per billion

All test results

Date Lab ID Result