Water Quality

The District purchases raw water from the Contra Costa Water District via the Contra Costa Canal. This raw water originates in either Rock Slough or Old River (from the San Joaquin River). Los Vaqueros Reservoir stores high quality raw water which is piped from Old River and can be used when needed.

Water is treated at the modern Randall-Bold Water Treatment Plant, which is jointly owned by Diablo Water District and Contra Costa Water District. The water treatment plant uses the best available technology and includes many innovations to ensure reliability and high quality drinking water. As noted below:

  • Removal of particles through sedimentation.
    Disinfection with ozone, which is more effective in eliminating bacteria than chlorine.
  • Filtration through 65 inches of granular activated carbon and 10 inches of sand.
  • Chloramination in minute quantities to continually disinfect the water in the pipeline until it reaches your home.
  • Supervision around-the-clock by State-certified professionals using a computer-controlled monitoring system.
  • Modern Day Security. The District has increased security with new physical barriers, alarms, patrols, ozone disinfection and additional water quality testing.