Casitas Reservoir water level chart
By Michael, independent developer behind zovo.one. Latest CDEC month October 2026.
CDEC's latest monthly storage figure for Casitas Reservoir is 225,058 acre-feet, for October 2026, 95 percent of its 238,000 acre-foot capacity. It is the 14th highest of the 56 October figures from 1971 to 2026.
Where October 2026 sits in 65 years of readings
CDEC's latest monthly storage figure for Casitas Reservoir is 225,058 acre-feet for October 2026. That is 95 percent of its 238,000 acre-foot capacity.
The file holds 56 October figures from 1971 to 2026. This one is the 14th highest of them. The average October figure across those years is 189,117 acre-feet, so the lake holds 119 percent of its average for the month.
Across every month from January 1971 on, 427 of 668 months were lower than today. That is 64 percent of those months.
The record low and the record high
The lowest monthly figure since January 1971 is 70,878 acre-feet, in November 2022. The highest is 260,280 acre-feet, in February 1998. That high is above the capacity CDEC lists today.
CDEC lists 1970 as the year Casitas Reservoir first filled. So the ranks, the average and the record low on this page count months from January 1971 on. That boundary is ours, not CDEC's. The file itself starts in October 1961. Its lowest figure, 3,270 acre-feet in October 1961, 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 1971, where the ranks start.
Want today's elevation and percent full rather than the monthly record? The Casitas Reservoir water level page carries the latest daily CDEC reading.
Questions about the Casitas Reservoir record
How far back does this chart go? To October 1961, the first month in CDEC's monthly storage file for station CSI. The file carries 779 monthly readings through October 2026.
Is Casitas Reservoir low for October? It is the 14th highest of 56 October readings, at 119 percent of the October average.
What is the lowest it has been? 70,878 acre-feet in November 2022, counting from January 1971.
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 CSI. 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, Lake Berryessa, Folsom Lake, Pine Flat Lake, Lake Isabella, Millerton Lake, New Melones Lake, Don Pedro Reservoir, San Luis Reservoir and Cachuma Lake. 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.