EWG's Tap Water Database



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
20102.86 ppb112.86 ppb
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

Health Guideline 0.15 ppb

The 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.

ppb = parts per billion.

EPA Maximum Contaminant
Level (MCL) 5 ppb

The enforceable federal standard that defines the highest level of a contaminant allowed in drinking water.

ppb = parts per billion.

EPA Maximum Contaminant
Level Goal (MCLG)0 ppb

A non-enforceable federal health guideline. For cancer-causing chemicals, these health goals are typically set to zero.

ppb = parts per billion.

All test results

Date Lab ID Result
2010-08-26V100826053-0012.86 ppb
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