Who We Are


Who We Are

Central San is a special district of the State of California. Special Districts are local public agencies formed by residents of a community to provide specific services.

Central San is a member of the California Special Districts Association (CSDA) and CSDA’s local chapter, the Contra Costa Special Districts Association. To learn more visit: www.csda.net or https://contracostasda.specialdistrict.org/ 

Central San provides wastewater collection, treatment, and disposal services; recycled water production and distribution; and household hazardous waste collection. Central San serves nearly half a million residents and more than 3,000 businesses within a 145-square-mile service area, which includes Alamo, Danville, Lafayette, Moraga, Orinda, Pleasant Hill, Walnut Creek; portions of Martinez and San Ramon; and unincorporated communities within central Contra Costa County. Central San also cleans the wastewater from the cities of Concord and Clayton, and they maintain their collection systems.

Vision, Mission & Values

Established in 1946, Central San is a special enterprise district with a five-member elected Board of Directors.

Our Vision

To be a high-performance organization that provides exceptional customer service and regulatory compliance at responsible rates.

Our Mission

To protect public health and the environment.

Our Values

  • Value customers and employees
  • Respect each other
  • Work as a team
  • Work effectively and efficiently
  • Celebrate our successes and learn from our challenges
  • Value water sector partners
  • Foster excellent community relationships
  • Be open, transparent and accessible
  • Understand service level expectations
  • Build partnerships
  • Be truthful and honest
  • Be fair, kind and friendly
  • Take ownership and responsibility
Leadership and Commitment
  • Promote a passionate and empowered workforce
  • Encourage continuous growth and development
  • Inspire dedication and top-quality results
  • Provide a safe and healthful environment

A Brief History

In the 1940s, central Contra Costa County was a rural area of farms, orchards and a few small towns. With the end of World War II, a building boom began. As the nearby cities of San Francisco, Oakland and Berkeley grew, so did the population of Contra Costa County.

This ultimately resulted in a sanitation crisis with most of the county depending on septic systems, often inefficient due to the area’s heavy adobe clay soil. At the time, State health authorities considered the polluted conditions arising from those septic tanks to be among the worst in California.

With septic tanks overflowing and waterborne diseases such as typhoid becoming a potential threat, civic leaders rallied public support for a solution. In an election held on June 24, 1946, a proposal to form a sanitary district for areas of central Contra Costa County was approved. On July 15, 1946, the County Board of Supervisors passed a resolution officially creating the Central Contra Costa Sanitary District (Central San).

Work began immediately and within 26 months, Central San’s newly constructed main sewer trunk line and treatment plant were operational. At that time, Central San’s service area population was 15,000; the treatment plant’s capacity was 4.5 million gallons per day; and the  collection system consisted of 50 miles of sewer pipe.

That original system was expected to handle the area’s wastewater for at least two decades. But by 1952, it was obvious that demand would soon exceed capacity. Central San began a series of expansions and improvements to meet the needs of a rapidly growing population – activities that have continued throughout the District’s history.

Enormous changes have occurred since the District’s beginnings in 1946 as a small agency serving a rural area: the size, population, and characteristics of our service area; the processes and technologies used to treat and collect wastewater; the environmental awareness and stricter water quality standards and regulations.  What hasn’t changed is our unwavering dedication and commitment to protecting the public health and the environment.

Watch a visual profile of Central San!

Who We Are


Collection System Renovation Projects

Project-specific information such as descriptions, maps, and contacts can be found here.


Project Description The Danville Sewer Renovation Project, Phase 4 will replace approximately 1.75 miles of sewers primarily in the Greenbrook, Del Amigo, Creeks of Alamo, and Camille neighborhoods of Danville and Alamo.


Service Area & Statistics

Service Area Map

Central San collects and cleans more than 13 billion gallons of wastewater per year for nearly 500,000 residents and more than 3,000 businesses in central Contra Costa County.