Reservoir · California · United States · CDEC
LAKE MC SWAIN
105.0% full
Capacity
10.18 hm³
Volume stored
11 hm³
Coordinates
37.520°N, 120.309°W
Last updated
2026-09-16
Current fill
105.0%vs 7 days ago
0.0%stable
vs 1 year ago
0.0%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: 2026-09-16.
Catchment Weather
Past 30 days + 14-day forecast · Open-Meteo
Satellite imagery: Esri, Maxar, Earthstar Geographics. Map: Esri, HERE, Garmin, © OpenStreetMap contributors. 37.520, -120.309 · Open in Google Maps
About LAKE MC SWAIN
As of September 16, 2026, LAKE MC SWAIN is filled to 105.0% of its total capacity, holding roughly 11 hm³ of water out of a maximum 10 hm³. At this level the reservoir is effectively full.
Over the most recent week on record the fill level has held broadly steady (+0.0 pts), and it sits close to where it was a year earlier.
Across the readings we hold for LAKE MC SWAIN — 1813 data points between September 19, 2021 and September 16, 2026 — the level has ranged from a low of 69.7% (December 1, 2025) to a high of 105.0% (September 19, 2021). On average the reservoir is fullest around April and at its lowest around November.
It is operated by CDEC primarily for multiple purposes. It lies within the California basin at 37.520°N, 120.309°W.
Key facts
- Current fill level
- 105.0%
- Water stored
- 11 hm³
- Total capacity
- 10 hm³
- 7-day change
- No change
- Year-on-year
- No change
- Primary use
- Multipurpose
- River basin
- California
- Operator
- CDEC
- Coordinates
- 37.520°N, 120.309°W
- Last updated
- September 16, 2026
Recent readings
| Date | Fill level | Volume (hm³) |
|---|---|---|
| 16 Sep 2026 | 105.0% | 11 |
| 15 Sep 2026 | 105.0% | 11 |
| 14 Sep 2026 | 103.6% | 11 |
| 13 Sep 2026 | 95.5% | 10 |
| 12 Sep 2026 | 100.4% | 10 |
| 11 Sep 2026 | 105.0% | 11 |
| 10 Sep 2026 | 105.0% | 11 |
| 9 Sep 2026 | 105.0% | 12 |
| 8 Sep 2026 | 105.0% | 12 |
| 7 Sep 2026 | 105.0% | 11 |
| 6 Sep 2026 | 105.0% | 11 |
| 5 Sep 2026 | 105.0% | 11 |