A long-planned surface water project in Northern California took a major step forward with state regulators granting a critical approval. The State Water Resources Control Board has signed off on the final water right permit for the proposed Sites Reservoir, clearing the way for construction to potentially begin as early as summer 2027. The action advances a $6 billion plan to add a major new storage asset to California’s water system.
The off-stream reservoir is planned for Glenn and Colusa counties, north of Sacramento. As designed, Sites Reservoir would capture water from the Sacramento River during eligible high-flow periods and then store that water for use in prolonged dry conditions. Project sponsors and state officials position the facility as a tool to smooth out increasingly volatile hydrologic cycles and support supplies during future droughts.
According to information from the office of Gov. Gavin Newsom, the reservoir is expected to provide 1.5 million acre-feet of new storage capacity once completed. State officials note that this volume is enough water to supply more than 4.5 million homes for one year. With the approved permit in hand, California is now on track to deliver what would be the state’s largest new reservoir in more than half a century.
State leaders are framing the project within a broader shift in water management strategies driven by climate pressures. “Our water system was built for a climate that no longer exists,” said California Secretary for Natural Resources Wade Crowfoot. He added that adapting to current and future conditions requires the ability to capture water during “huge storms and wet winters” and then hold those supplies for use during “worsening droughts.” In his view, Sites Reservoir is designed to fulfill precisely that role.
The State Water Resources Control Board’s approval of the final water right permit represents a major regulatory milestone for the project. Water rights determinations are a central step in California’s project delivery process, particularly for large-scale storage proposals that depend on access to river flows during specific hydrologic windows. With this permit finalized, the focus for project stakeholders will shift toward implementation steps required to move from planning into the construction phase targeted to begin in 2027.
While key regulatory risk around water rights has now been significantly reduced, the Sites Reservoir plan still rests within a broader context of statewide water supply planning and infrastructure investment. The project’s scale, cost and operational objectives underscore the extent to which California is turning to additional storage to manage both flood and drought risk, using existing river systems and new off-stream capacity to better align water availability with demand over time.
