EWG's Tap Water Database — 2019 UPDATE



Cone Delfred Subdivision

Benzene is a known human carcinogen. It also damages blood cells and the nervous system. Emissions from petroleum processing, hazardous waste landfills and underground storage tanks contaminate drinking water with benzene. Read More.

To protect against cancer risks, California set a public health goal for benzene in drinking water at 0.15 parts per billion, 30 times lower than the federal legal limit 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
20121.12 ppb441.000 ppb - 1.25 ppb
20130.760 ppb440.550 ppb - 0.940 ppb
20140.550 ppb110.550 ppb

ppb = parts per billion

State and national drinking water standards and health guidelines

EWG Health Guideline 0.15 ppb

The EWG Health Guideline of 0.15 ppb for benzene 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 benzene, established in 1987, 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 benzene exposure.

ppb = parts per billion

All test results

Date Lab ID Result
2012-03-23120323005-0011.25 ppb
2012-06-13120614051-0011.21 ppb
2012-09-19120920006-0011.03 ppb
2012-12-12121213004-0011.000 ppb
2013-03-15V130315026-0010.550 ppb
2013-06-11130613015-0010.940 ppb
2013-09-18V130919037-0010.770 ppb
2013-12-1113122069-0010.780 ppb
2014-09-23140924006-0010.550 ppb