The Environmental Water Caucus was formed in 1991 to facilitate the involvement of environmental, civic, recreational, and commercial fishing organizations in achieving sustainable water management solutions for California. Active members include virtually every group advocating for equitable and sustainable California water resource use.

The EWC promotes collaborative public processes to decrease conflicts over California water for a stronger economy, healthier environment and a fully involved California public. The EWC advocates for the restoration of the aquatic ecosystems and fisheries of the San Francisco Bay, Sacramento/San Joaquin Delta, and Central Valley, as well as improvements in water quality and protection of public trust values. The EWC and its member organizations promote projects that will reduce the demand for water that would normally flow to and through the Bay-Delta, and oppose water projects that will negatively impact aquatic ecosystems.