EWG's Tap Water Database — 2021 UPDATE


1,2-Dibromo-3-chloropropane (DBCP)

San Juan Vista

1,2-Dibromo-3-chloropropane is a pesticide fumigant banned in the 1970s after scientists discovered it caused sterility in men who worked with it. The chemical causes cancer in laboratory animals and may cause cancer in people. Read More.

This pesticide breaks down very slowly in the environment. It remains in groundwater and drinking water wells in the agricultural areas where it was sprayed in the past. Men exposed to this pesticide in the fields suffered from infertility and testicular damage, and tended to have fewer male babies.





Samples exceeding legal limit (MCL)


Samples exceeding
health guidelines

Testing results - average by year

YearAverage resultSamples takenDetectionsRange of results
20160.0130 ppb21ND - 0.0260 ppb
20170.0220 ppb220.0200 ppb - 0.0240 ppb
20180.0270 ppb110.0270 ppb
20190.0270 ppb110.0270 ppb

ppb = parts per billion

State and national drinking water standards and health guidelines

EWG Health Guideline 0.0017 ppb

The EWG Health Guideline of 0.0017 ppb for 1,2-dibromo-3-chloropropane 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) 0.2 ppb

The legal limit for 1,2-dibromo-3-chloropropane, 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 1,2-dibromo-3-chloropropane exposure.

ppb = parts per billion

All test results

Date Lab ID Result
2016-06-085810-001-12250.0260 ppb
2017-06-295810-001-11200.0240 ppb
2017-07-261120-001-14350.0200 ppb
2018-06-015810-001-13230.0270 ppb
2019-06-125810-001-12050.0270 ppb