Lake Berryessa water level chart
By Michael, independent developer behind zovo.one. Latest CDEC month October 2026.
CDEC's latest monthly storage figure for Lake Berryessa is 1,322,292 acre-feet, for October 2026, 83 percent of its 1,602,000 acre-foot capacity. It is the 28th highest of the 62 October figures from 1965 to 2026.
Where October 2026 sits in 69 years of readings
CDEC's latest monthly storage figure for Lake Berryessa is 1,322,292 acre-feet for October 2026. That is 83 percent of its 1,602,000 acre-foot capacity.
The file holds 62 October figures from 1965 to 2026. This one is the 28th highest of them. The average October figure across those years is 1,175,068 acre-feet, so the lake holds 113 percent of its average for the month.
Across every month from January 1965 on, 315 of 741 months were lower than today. That is 43 percent of those months.
The record low and the record high
The lowest monthly figure since January 1965 is 422,230 acre-feet, in November 1992. The highest is 1,707,000 acre-feet, in February 1983. That high is above the capacity CDEC lists today.
CDEC lists 1964 as the year Lake Berryessa first filled. So the ranks, the average and the record low on this page count months from January 1965 on. That boundary is ours, not CDEC's. The file itself starts in October 1957. Its lowest figure, 122,950 acre-feet in October 1957, comes from before that boundary, so the comparisons leave it out.
How to read this chart
The line is storage, the volume of water in the reservoir, in acre-feet. It is not the surface elevation. CDEC publishes storage as one figure per month back to the start of the record, which is why this chart uses it. The dashed line is the capacity CDEC lists for the reservoir. The dotted line marks January 1965, where the ranks start.
Want today's elevation and percent full rather than the monthly record? The Lake Berryessa water level page carries the latest daily CDEC reading.
Questions about the Lake Berryessa record
How far back does this chart go? To October 1957, the first month in CDEC's monthly storage file for station BER. The file carries 828 monthly readings through October 2026.
Is Lake Berryessa low for October? It is the 28th highest of 62 October readings, at 113 percent of the October average.
What is the lowest it has been? 422,230 acre-feet in November 1992, counting from January 1965.
How often does this page update? The build fetches the CDEC file again every day and recomputes each figure. A new month shows up once CDEC publishes it.
Where these numbers come from
Every figure on this page is computed in code from CDEC's monthly reservoir storage file for station BER. The capacity and the first fill year come from CDEC's reservoir information page for the station. The build drops months that CDEC marks as missing. None of the numbers is typed by hand.
The same chart exists for 11 other California lakes. They are Shasta Lake, Lake Oroville, Folsom Lake, Pine Flat Lake, Lake Isabella, Millerton Lake, New Melones Lake, Don Pedro Reservoir, San Luis Reservoir, Cachuma Lake and Casitas Reservoir. The California lake levels page covers every reservoir in CDEC's daily storage summary.
Levels are point-in-time readings and can lag real conditions. Confirm ramp and hazard status with the lake operator before heading out. Not affiliated with any government agency. Data is republished from public USGS, CDEC and USBR feeds.