Reservoir · California · United States · CDEC
LAKE MC SWAIN
105.0% full
Capacity
10.18 hm³
Volume stored
11 hm³
Vs month average
104% of normal
Coordinates
37.520°N, 120.309°W
Last updated
2026-10-31
Current fill
105.0%vs 23 Oct 2026
+4.7 ppgaining
vs 1 year ago
+0.6 ppyear-over-year
Trend
↑rising
Drought context
Storage vs October average
104%of normal
105.0% full on 2026-10-31, against an average of 100.6% for October across 5 years of readings (+4.4 points).
Drought Monitor at this site · 27 October 2026
D0abnormally dry
The ground at LAKE MC SWAIN's coordinates falls inside the D0 area of the weekly U.S. Drought Monitor map. That describes local conditions — rainfall, soil moisture, streamflow — not the reservoir's storage. California drought figures →
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: 2026-10-31.
Catchment Weather
Past 30 days + 14-day forecast · Open-Meteo
Satellite imagery: Esri, Maxar, Earthstar Geographics. Map: Esri, HERE, Garmin, © OpenStreetMap contributors. 37.520°N, 120.309°W · Open in Google Maps
About LAKE MC SWAIN
As of October 31, 2026, LAKE MC SWAIN has a published fill of 105.0%, holding 10.93 hm³. Total capacity is 10.18 hm³. At this level the reservoir is effectively full.
Since October 23, 2026 the fill level has risen by 4.7 percentage points, and it sits close to where it was a year earlier.
Across the readings we hold for LAKE MC SWAIN — 664 data points between November 4, 2021 and October 31, 2026 — the level has ranged from a low of 69.7% (December 1, 2025) to a high of 105.0% (October 31, 2026). On average the reservoir is fullest around April and at its lowest around November.
It is operated by CDEC primarily for multiple purposes. It is at 37.520°N, 120.309°W.
Key facts
- Current fill level
- 105.0%
- Water stored
- 10.93 hm³
- Total capacity
- 10.18 hm³
- Change since October 23, 2026
- ▲ 4.7 pp
- Year-on-year
- ▲ 0.6 pp
- Primary use
- Multipurpose
- Operator
- CDEC
- Coordinates
- 37.520°N, 120.309°W
- Last updated
- October 31, 2026
Recent readings
| Date | Fill level | Volume (hm³) |
|---|---|---|
| 31 Oct 2026 | 105.0% | 10.93 |
| 30 Oct 2026 | 102.9% | 10.48 |
| 29 Oct 2026 | 103.8% | 10.57 |
| 23 Oct 2026 | 100.3% | 10.21 |
| 22 Oct 2026 | 102.1% | 10.39 |
| 10 Oct 2026 | 104.0% | 10.59 |
| 9 Oct 2026 | 102.9% | 10.48 |
| 8 Oct 2026 | 103.9% | 10.58 |
| 7 Oct 2026 | 104.8% | 10.67 |
| 2 Oct 2026 | 104.5% | 10.64 |
| 28 Sep 2026 | 102.9% | 10.48 |
| 27 Sep 2026 | 98.8% | 10.06 |