Reservoir · California · United States · CDEC
SAN ANTONIO RESERVOIR, ALAMEDA CO
86.3% full
Capacity
62.29 hm³
Volume stored
54 hm³
Vs month average
92% of normal
Coordinates
37.573°N, 121.848°W
Last updated
2026-10-13
Current fill
86.3%vs 7 days ago
-0.2%losing
vs 1 year ago
-11.4%year-over-year
7-day trend
→stable
Drought context
Storage vs October average
92%of normal
86.3% full on 2026-10-13, against an average of 94.2% for October across 6 years of readings (-7.9 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: 2026-10-13.
Catchment Weather
Past 30 days + 14-day forecast · Open-Meteo
Satellite imagery: Esri, Maxar, Earthstar Geographics. Map: Esri, HERE, Garmin, © OpenStreetMap contributors. 37.573, -121.848 · Open in Google Maps
About SAN ANTONIO RESERVOIR, ALAMEDA CO
As of October 13, 2026, SAN ANTONIO RESERVOIR, ALAMEDA CO is filled to 86.3% of its total capacity, holding roughly 54 hm³ of water out of a maximum 62 hm³. At this level the reservoir is high.
Over the most recent week on record the fill level has held broadly steady (-0.2 pts), and it is 11.4 points below its level on the same date a year earlier.
Across the readings we hold for SAN ANTONIO RESERVOIR, ALAMEDA CO — 1797 data points between October 16, 2021 and October 13, 2026 — the level has ranged from a low of 73.7% (March 11, 2022) to a high of 105.0% (December 31, 2022). On average the reservoir is fullest around June and at its lowest around March.
It is operated by CDEC primarily for multiple purposes. It lies within the California basin at 37.573°N, 121.848°W.
Key facts
- Current fill level
- 86.3%
- Water stored
- 54 hm³
- Total capacity
- 62 hm³
- 7-day change
- ▼ 0.2 pts
- Year-on-year
- ▼ 11.4 pts
- Primary use
- Multipurpose
- River basin
- California
- Operator
- CDEC
- Coordinates
- 37.573°N, 121.848°W
- Last updated
- October 13, 2026
Recent readings
| Date | Fill level | Volume (hm³) |
|---|---|---|
| 13 Oct 2026 | 86.3% | 54 |
| 12 Oct 2026 | 86.3% | 54 |
| 11 Oct 2026 | 86.3% | 54 |
| 10 Oct 2026 | 86.3% | 54 |
| 9 Oct 2026 | 86.4% | 54 |
| 8 Oct 2026 | 86.4% | 54 |
| 7 Oct 2026 | 86.5% | 54 |
| 6 Oct 2026 | 86.5% | 54 |
| 5 Oct 2026 | 86.5% | 54 |
| 4 Oct 2026 | 86.5% | 54 |
| 3 Oct 2026 | 86.6% | 54 |
| 2 Oct 2026 | 86.6% | 54 |