Service Area & Statistics


Service Area Map

Central San collects and cleans an average of 35 million gallons of wastewater per day for about 488,900 residents and 3,000 businesses in central Contra Costa County.


Central Contra Costa Sanitary

  • Established in 1946 as a special enterprise district
  • Serves approximately 488,900 residents and 3,000 businesses in 13 cities and towns covering a 144-square mile area
  • Employs 281 dedicated professionals

Treatment Plant

  • Collects and cleans an average of 35 million gallons of wastewater per day
  • The furnace incinerates approximately 200 tons of sludge per day, reducing that volume to only 14 tons of sterile ash that is used in commercial fertilizers.
  • The cogeneration facility uses natural gas to produce electricity and steam to power the plant. Approximately 3,200 kilowatts (80-90% of the plant’s daily power needs) are produced, saving approximately $500,000 each year on energy costs.
  • Produces approximately 600 million gallons of recycled water each year for plant operations, industrial uses, and landscape irrigation


  • Environmental Laboratory performs approximately 15,000 chemical and biological tests each year. Some tests measure on a parts-per-quadrillion range.

Collection System

  • Maintains, cleans, and repairs 1,540 miles of sewer lines and 18 pumping stations

Household Hazardous Waste Collection Facility

  • District operates a Household Hazardous Waste Collection Facility (HHWCF), established in 1997, collecting approximately two-million pounds of household hazardous waste per year, 90% of which is reused or recycled.


  • The 2017-18 Fiscal Year budget is $132.5 million.

The Communities We Serve and Links to their Websites (where available)