The San Gabriel Basin Water Quality Authority (WQA) was established by the State Legislature (SB1679) on February 11, 1993, to develop, finance, and implement groundwater treatment programs in the San Gabriel Basin. 

The San Gabriel Basin is the primary source of drinking water for more than 1 million people in Alhambra, Irwindale, La Puente, Rosemead, Azusa, Baldwin Park, City of Industry, El Monte, South El Monte, West Covina and other areas of the San Gabriel Valley. 

In 1979, industrial solvents and other contaminants were identified in groundwater in the San Gabriel Valley. The contamination at the site is believed to be the result of decades of improper chemical handling and disposal practices. As a result, water suppliers had to shut down wells and large portions of the basin were placed on the federal Superfund cleanup list in 1984. The WQA was created to manage and coordinate the cleanup with local, state, and federal agencies. 

Cleanup so far has cost about $500 million, which came from public funds and the parties responsible for the contamination. WQA-sponsored projects represent more than half of the total contaminants removed from the Basin.


  • The San Gabriel Basin is 689 square miles.

  • The Basin is divided into six treatment zones.

  • WQA-sponsored projects have removed nearly 45 tons of contaminants from the San Gabriel Valley groundwater basin.

  • WQA projects represent more than 50 percent of the total contaminants removed from the basin since 1979.

  • WQA assessments to accomplish cleanup of the Basin average $7.25 per household per year.


Executive Director

Assistant Executive Director/Senior Project Manager

Director of Finance

Executive Assistant/Public Outreach Coordinator

Administrative/Accounting Assistant