Reservoir · California · United States · CDEC
WARM SPRINGS (LAKE SONOMA)
96.2% full
Capacity
302.2 hm³
Volume stored
291 hm³
Coordinates
38.723°N, 123.010°W
Last updated
2026-09-17
Current fill
96.2%vs 7 days ago
-0.7%losing
vs 1 year ago
+1.2%year-over-year
7-day trend
→stable
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: 2026-09-17.
Catchment Weather
Past 30 days + 14-day forecast · Open-Meteo
Satellite imagery: Esri, Maxar, Earthstar Geographics. Map: Esri, HERE, Garmin, © OpenStreetMap contributors. 38.723, -123.010 · Open in Google Maps
About WARM SPRINGS (LAKE SONOMA)
As of September 17, 2026, WARM SPRINGS (LAKE SONOMA) is filled to 96.2% of its total capacity, holding roughly 291 hm³ of water out of a maximum 302 hm³. At this level the reservoir is high.
Over the most recent week on record the fill level has held broadly steady (-0.7 pts), and it is 1.2 points above its level on the same date a year earlier.
Across the readings we hold for WARM SPRINGS (LAKE SONOMA) — 1822 data points between September 19, 2021 and September 17, 2026 — the level has ranged from a low of 39.3% (December 9, 2022) to a high of 105.0% (March 8, 2023). On average the reservoir is fullest around March and at its lowest around November.
It is operated by CDEC primarily for multiple purposes. It lies within the California basin at 38.723°N, 123.010°W.
Key facts
- Current fill level
- 96.2%
- Water stored
- 291 hm³
- Total capacity
- 302 hm³
- 7-day change
- ▼ 0.7 pts
- Year-on-year
- ▲ 1.2 pts
- Primary use
- Multipurpose
- River basin
- California
- Operator
- CDEC
- Coordinates
- 38.723°N, 123.010°W
- Last updated
- September 17, 2026
Recent readings
| Date | Fill level | Volume (hm³) |
|---|---|---|
| 17 Sep 2026 | 96.2% | 291 |
| 16 Sep 2026 | 96.3% | 291 |
| 15 Sep 2026 | 96.4% | 291 |
| 14 Sep 2026 | 96.5% | 292 |
| 13 Sep 2026 | 96.6% | 292 |
| 12 Sep 2026 | 96.7% | 292 |
| 11 Sep 2026 | 96.8% | 292 |
| 10 Sep 2026 | 96.9% | 293 |
| 9 Sep 2026 | 97.0% | 293 |
| 8 Sep 2026 | 97.1% | 293 |
| 7 Sep 2026 | 97.2% | 294 |
| 6 Sep 2026 | 97.3% | 294 |