Reservoir · California · United States · CDEC
BUTT VALLEY
79.7% full
Capacity
61.43 hm³
Volume stored
49 hm³
Vs month average
97% of normal
Coordinates
40.148°N, 121.174°W
Last updated
2026-10-07
Current fill
79.7%vs 7 days ago
-9.5%losing
vs 1 year ago
+2.4%year-over-year
7-day trend
↓falling
Drought context
Storage vs October average
97%of normal
79.7% full on 2026-10-07, against an average of 81.8% for October across 6 years of readings (-2.1 points).
Data source: CDEC — California Dept of Water Resources — daily reservoir storage volume. Capacity is the design (normal full-pool) capacity from the US National Inventory of Dams (NID); fill % = current volume ÷ design capacity. Last reading: 2026-10-07.
Catchment Weather
Past 30 days + 14-day forecast · Open-Meteo
Satellite imagery: Esri, Maxar, Earthstar Geographics. Map: Esri, HERE, Garmin, © OpenStreetMap contributors. 40.148, -121.174 · Open in Google Maps
About BUTT VALLEY
As of October 7, 2026, BUTT VALLEY is filled to 79.7% of its total capacity, holding roughly 49 hm³ of water out of a maximum 61 hm³. At this level the reservoir is within its normal operating range.
Over the most recent week on record the fill level has fallen by 9.5 percentage points, and it is 2.4 points above its level on the same date a year earlier.
Across the readings we hold for BUTT VALLEY — 1817 data points between October 16, 2021 and October 7, 2026 — the level has ranged from a low of 67.0% (January 22, 2026) to a high of 96.9% (August 29, 2026). On average the reservoir is fullest around June and at its lowest around January.
It is operated by CDEC primarily for multiple purposes. It lies within the California basin at 40.148°N, 121.174°W.
Key facts
- Current fill level
- 79.7%
- Water stored
- 49 hm³
- Total capacity
- 61 hm³
- 7-day change
- ▼ 9.5 pts
- Year-on-year
- ▲ 2.4 pts
- Primary use
- Multipurpose
- River basin
- California
- Operator
- CDEC
- Coordinates
- 40.148°N, 121.174°W
- Last updated
- October 7, 2026
Recent readings
| Date | Fill level | Volume (hm³) |
|---|---|---|
| 7 Oct 2026 | 79.7% | 49 |
| 6 Oct 2026 | 81.7% | 50 |
| 5 Oct 2026 | 82.9% | 51 |
| 4 Oct 2026 | 84.8% | 52 |
| 3 Oct 2026 | 88.2% | 54 |
| 2 Oct 2026 | 88.7% | 54 |
| 1 Oct 2026 | 87.7% | 54 |
| 30 Sep 2026 | 89.2% | 55 |
| 29 Sep 2026 | 86.2% | 53 |
| 28 Sep 2026 | 87.7% | 54 |
| 27 Sep 2026 | 85.2% | 52 |
| 26 Sep 2026 | 85.0% | 52 |