CVP vs SWP: California's two big water projects, explained

The Central Valley Project and the State Water Project are California's two great water-moving systems, and they are easy to confuse because they overlap physically. The short version: the CVP is federal and agricultural, the SWP is state and urban, and both pull water through the same Sacramento-San Joaquin Delta.

Who runs them and who they serve

The CVP is operated by the US Bureau of Reclamation, a federal agency, and it was built to water the Central Valley. Most of its supply goes to Valley agriculture, with major deliveries to wildlife refuges. The SWP is operated by the California Department of Water Resources, a state agency, and it leans urban. Its dominant customer is the Metropolitan Water District serving Southern California cities, with San Joaquin Valley farms taking a share.

The shared Delta is the catch

Both projects move water from the wetter north of the state to the drier south, and both do it by pulling supply through the Delta with big pumps near Tracy. That shared plumbing is the key constraint. When Delta conditions tighten, for fish protection, salinity or storm operations, both projects feel it at once, which is why a bad Delta year can pull both allocations down together.

Side by side

The two projects announce separately and on different calendars, so the live numbers rarely match.

Above are a representative CVP class, south-of-Delta agricultural service, and the statewide SWP allocation, each current. A quick reference for the rest:

• Operator: CVP is federal (Reclamation). SWP is state (DWR).
• Core customers: CVP is Valley ag plus refuges. SWP is Southern California cities plus some ag.
• First announcement: CVP around late February. SWP around December 1.
• Contract basis: CVP is a percent of contract volume by class. SWP is a percent of Table A amounts.

For the mechanics of each, see the CVP allocations guide and the SWP allocations guide.