San Luis Reservoir Water Level Today - 485.07 ft, 65.6% Full

B.F. Sisk Dam · San Luis Creek (offstream) · California - updated daily from official gauges

Western Reservoir Conditions·Daily·No. 47·Tuesday, September 8, 2026·Latest reading September 7, 2026

• San Luis Reservoir is 65.6% full - moderate on this site's capacity scale - as of September 7, 2026. Surface elevation 485.07 feet, storage 1,339,733 acre-feet (capacity basis 2,041,000 acre-feet), per California DWR (CDEC) gauge data.
• That elevation is its highest September reading since 2023, and 140.11 feet above its record low of 344.96 ft (August 24, 1989), in a daily record going back to January 4, 1988 (start of CDEC's daily record).
• Storage is 169% of the September 7 average across 39 years of record.
• San Luis Reservoir is rising: elevation changed +4.78 ft over the past week, +17.19 ft over the past month, and +42.77 ft over the past year, per California DWR (CDEC) gauge data.

San Luis Reservoir has risen 42.77 feet in twelve months, to 169% of its September 7 storage average.

San Luis Reservoir vs its record low

In the daily record used by this site (going back to January 4, 1988 (start of CDEC's daily record)), San Luis Reservoir's lowest surface elevation was 344.96 feet on August 24, 1989, when storage was 160,927 acre-feet. As of September 7, 2026, San Luis Reservoir is at 485.07 feet - 140.11 feet above that record. The record high in the same series was 544.17 ft on March 14, 1995.

San Luis Reservoir storage in context

San Luis Reservoir water level, past 12 months

65.6% full at the latest reading - across the past 12 months it ranged from 43.9% (September 7, 2025) to 89.0% (March 25, 2026). Percent full is storage against the 2,041,000-acre-foot capacity basis, not a share of the elevation plotted above.

San Luis Reservoir elevation, full record

65.6% full at the latest reading - across the storage record since January 4, 1988 it ranged from 7.9% (August 24, 1989) to 100.9% (March 21, 1995). Percent full is storage against the 2,041,000-acre-foot capacity basis, not a share of the elevation plotted above. Every percentage here is measured against today's capacity basis; a reservoir's surveyed capacity changes as sediment accumulates behind the dam, so early-record percentages are indicative rather than exact.

Last 14 daily readings

Frequently asked questions

What is the water level of San Luis Reservoir today?

As of September 7, 2026, San Luis Reservoir's surface elevation is 485.07 feet, with 1,339,733 acre-feet in storage - 65.6% of the 2,041,000 acre-foot capacity basis. Source: California DWR CDEC daily gauge data.

How full is San Luis Reservoir?

San Luis Reservoir is 65.6% full as of September 7, 2026. Its storage is 169% of the September 7 average across its record since 1988. Source: California DWR CDEC daily gauge data.

When was San Luis Reservoir last full?

San Luis Reservoir was last at or above 95% of its 2,041,000 acre-foot capacity basis on July 13, 2023. As of September 7, 2026 it is 65.6% full. Source: California DWR CDEC daily gauge data.

Is San Luis Reservoir rising or falling?

San Luis Reservoir is rising: its elevation changed +4.78 feet over the week ending September 7, 2026, +17.19 ft over the past month, and +42.77 feet over the past year. Source: California DWR CDEC daily gauge data.

What was San Luis Reservoir's lowest water level on record?

San Luis Reservoir's lowest surface elevation in the daily record since January 4, 1988 was 344.96 feet on August 24, 1989, per the daily record used by this site. As of September 7, 2026 the reservoir is 140.11 feet above that record low.

About this gauge

San Luis Reservoir near Los Banos is the largest offstream reservoir in the United States, shared by the federal Central Valley Project and the State Water Project. It is filled by pumping in the wet season and drawn down through summer, so large seasonal swings are normal.

Operator

California Department of Water Resources (CDEC)

Station

Station SNL

Measurements

Sensor 6 (reservoir elevation), sensor 15 (storage), daily

Dam

B.F. Sisk Dam

River

San Luis Creek (offstream)

State

California

Coordinates

37.0330, -121.1330 (CDEC station SNL metadata)

Full pool reference

544.0 ft

Capacity basis

2,041,000 acre-feet (CDEC daily reservoir storage summary)

Period of record

January 4, 1988 (start of CDEC's daily record)

Status

Provisional - subject to revision by the reporting agency

Update cadence

Daily

Download the daily CSV (date, elevation ft, storage AF) or see all data downloads.

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