In 1940, the Solano Board of Supervisors organized the Solano County Water Council.  The purpose of the water council was to study the areas of greatest water need and promote general water development in Solano County. Eight years later, in 1948, the Solano Irrigation District was founded with a mission to secure irrigation water from the newly proposed Solano Water Project.

For more detailed information about the history of the Solano Water Project, see:

For more detailed information about the history of the Solano Irrigation District, see:

The Solano Irrigation District (SID) provides 141,000 acre-feet of irrigation water to over 59,000 acres of irrigable land.  We supply bulk untreated water for a residential population of more than 300,000, including the cities of Benicia, Vacaville, Fairfield and Vallejo. SID also treats and delivers drinking water to Suisun City.  SID is the largest special district in Solano County and was formed under the Water Code of the State of California as an irrigation district. Members of the Board of Directors are elected by voters at-large throughout the District to four-year overlapping terms.

The Board of Directors sets all policy for the District, approves the annual budget and appoints the Secretary/Manager (General Manager), who serves at the pleasure of the Board. The General Manager is responsible for the day-to-day operations of the District with 81 employees. These employees provide an array of technical and support functions for the District and its customers.

SID is a financially stable, well managed, district that provides cost-efficient services while maintaining stable water rates. Our operating and capital budget is approximately $10.5 million annually. The District receives revenues from multiple funding sources and is not part of the State Water Project.


SID performs a variety of water resource-related functions, the combination of which is not typical of most irrigation districts in California. The physical assets and water rights that SID owns convey both raw and treated water to other local agencies. As a result of the foresight of forward-thinking leaders in the early part of the century, SID has secured valuable water rights and access through ‘The Solano Project’.  SID operates and maintains The Solano Project project, which is comprised of the Monticello Dam (forming Lake Berryessa), the Putah Diversion Dam (forming Lake Solano), the Putah South Canal and the Terminal Reservoir, all of which are owned by the federal government. 

Unlike many other districts, SID does not have the need to import any water for its customers.


SID delivers the water ordered by its direct customers, the cities with which it has contracts, Maine Prairie, the University of California at Davis and the California Medical Facility. SID built a hydroelectric power plant at the base of Monticello Dam in 1980 and is the sole owner. This was the first hydro-project owned by a local agency at the base of a federal dam in the United States. PG&E has agreed to buy all the energy produced at the plant and pays all the expenses to operate the plant. This long-term lease agreement will expire in 2031 and it is anticipated that the District at that time will be able to openly sell this power which in turn will bring revenue to the District, ultimately lowering the cost of water to the public served.

For more information about the Solano Project:
For more information about the Monticello Dam:
Domestic Water Delivery
SID a partnership in water service under “joint powers” arrangements to treat and supply water to residents and businesses to the City of Suisun City. In this capacity, SID operates and maintains both conventional and membrane treatment facilities, groundwater wells and distribution systems. SID also has a diverse group of domestic water customers, some of whom are direct customers who live in the unincorporated areas of the County.

Agricultural Water Delivery

SID owns and operates a water delivery system of about 370 miles of pipes, canals, and ditches. It delivers water to agricultural lands covering 65,000 acres in any one year (out of over 80,000 acres in the District). It also owns 32 wells, which supplement surface water deliveries.