Patterson Pass Water Treatment Plant


Large body of water with metal rods along the surface with green hills in the background.

The Patterson Pass Water Treatment Plant has been serving the Tri-Valley since 1962, treating imported surface water from the adjacent South Bay Aqueduct using dual-media filtration and chlorine treatment techniques. The plant is currently being upgraded to add ozone treatment.  The plant capacity will also be expanded from 12 million gallons per day (mgd) to 24 mgd.

The plant is currently undergoing major construction and will soon offer ozone treatment along with other major enhancements.

These upgrades will improve treated water quality with the added ozone facilities, replace aging equipment, increase treated water storage capacity with the addition of a new five-million-gallon tank and double the amount of treated water the plant can produce from 12 million gallons of water a day to 24 million gallons a day (MGD).

Patterson Pass Water Treatment Plant Fast Facts:

  • Location: Eastern Livermore
  • Treatment Capacity: 12 million gallons per day
  • Treatment Process: Dual-media filtration

Water tank filtering water.

Learn More

Construction Schedule: Construction began in March 2019 and is anticipated to be complete in spring 2022.

Project Cost: The project is estimated to cost $110 million for planning, design and construction and is funded by water rates, new connection fees and bonds.

FAQ: Updated project documents and progress reports provide more detailed information about the project.

Contact Information: For questions about this project, please contact Project Manager Mona Olmsted at (925) 454-5033 or by sending a message.

Small water treatment plant building with water tanks in the foreground and grassy hills in the background.

Grassy hills and mountain range surrounding water treatment reservoir.

Deep blue body of water.