Overview
Clear Lake is California's largest natural freshwater lake wholly within the state, covering about 43,790 acres when full across Lake County north of the Napa Valley. The ancient tectonic basin drains through Cache Creek to the Sacramento Valley. Outflow is regulated at Cache Creek Dam by the Yolo County Flood Control & Water Conservation District under long-standing court decrees that balance flood protection around the lake with downstream irrigation supply.
The lake stretches roughly 19 miles through three connected arms—Upper, Oaks, and Lower—with about 100 miles of shoreline, an average depth near 27 feet, and a maximum depth of about 60 feet. Broad, relatively shallow basins, tule-lined coves, rocky points, and a few small islands create a productive warmwater environment that is also prone to seasonal algae and turbidity swings.
Clear Lake is a major Northern California destination for bass fishing, boating, and lakeside recreation centered on communities such as Lakeport, Clearlake, and Clearlake Oaks. Fisheries are managed by the California Department of Fish and Wildlife, and public ramps, marinas, and parks ring much of the shore.
Water levels are reported on the historic Rumsey gauge at Lakeport, where zero Rumsey equals about 1,318.26 feet above mean sea level and a full lake is defined as 7.56 feet Rumsey (about 1,325.8 feet MSL). Court rules generally keep the lake between zero and 7.56 feet Rumsey, with limited flood exceptions up to about 9.0 feet Rumsey. Because summer irrigation releases and winter storms can move the pool quickly, monitoring current lake levels matters for docks, flooding risk, and fishing access.
Current Conditions
Clear Lake is currently 1.52 feet below full pool and has fallen slightly over the past week.
- 7-day trendFallingLatest movement can differ from the seven-day trend.
- 7-day changeDown 0.24 ft
- 30-day changeDown 1.04 ft
- Drought conditionsAbnormally Dry
About This Lake
Learn how this lake is managed, what affects its water level, and where Lake Insights gets its data.
Clear Lake is a 43,790-acre reservoir on the Scotts Creek managed by Yolo County Flood Control & Water Conservation District.