Reservoir · California · United States · CDEC
Hell Hole Reservoir
73.7% full
Capacity
255.33 hm³
Volume stored
188 hm³
Coordinates
39.058°N, 120.407°W
Last updated
2026-08-01
Current fill
73.7%vs 7 days ago
-3.4%losing
vs 1 year ago
+1.5%year-over-year
7-day trend
↓falling
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: 2026-08-01.
Catchment Weather
Past 30 days + 14-day forecast · Open-Meteo
Satellite imagery: Esri, Maxar, Earthstar Geographics. Map: Esri, HERE, Garmin, © OpenStreetMap contributors. 39.058, -120.407 · Open in Google Maps
About Hell Hole Reservoir
As of August 1, 2026, Hell Hole Reservoir is filled to 73.7% of its total capacity, holding roughly 188 hm³ of water out of a maximum 255 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 3.4 percentage points, and it is 1.5 points above its level on the same date a year earlier.
Across the readings we hold for Hell Hole Reservoir — 1818 data points between August 5, 2021 and August 1, 2026 — the level has ranged from a low of 26.4% (October 16, 2021) to a high of 101.3% (May 21, 2023). On average the reservoir is fullest around June and at its lowest around December.
It is operated by CDEC primarily for multiple purposes. It lies within the California basin at 39.058°N, 120.407°W.
Key facts
- Current fill level
- 73.7%
- Water stored
- 188 hm³
- Total capacity
- 255 hm³
- 7-day change
- ▼ 3.4 pts
- Year-on-year
- ▲ 1.5 pts
- Primary use
- Multipurpose
- River basin
- California
- Operator
- CDEC
- Coordinates
- 39.058°N, 120.407°W
- Last updated
- August 1, 2026
Recent readings
| Date | Fill level | Volume (hm³) |
|---|---|---|
| 1 Aug 2026 | 73.7% | 188 |
| 31 Jul 2026 | 74.1% | 189 |
| 29 Jul 2026 | 75.1% | 192 |
| 26 Jul 2026 | 76.4% | 195 |
| 25 Jul 2026 | 77.1% | 197 |
| 24 Jul 2026 | 77.7% | 198 |
| 23 Jul 2026 | 78.2% | 200 |
| 22 Jul 2026 | 78.7% | 201 |
| 21 Jul 2026 | 79.1% | 202 |
| 20 Jul 2026 | 79.5% | 203 |
| 19 Jul 2026 | 79.9% | 204 |
| 18 Jul 2026 | 80.3% | 205 |
Frequently asked questions
What is the current water level of Hell Hole Reservoir?
As of August 1, 2026, Hell Hole Reservoir is at 73.7% of its capacity, holding approximately 188 hm³ of water, according to CDEC (CA DWR) data.
Is Hell Hole Reservoir reservoir full?
No. As of August 1, 2026, Hell Hole Reservoir is within its normal operating range at 73.7% of its capacity, so it is not full.
Is the water level at Hell Hole Reservoir rising or falling?
The level at Hell Hole Reservoir is falling — it dropped 3.4 percentage points over the latest week on record.
How much water can Hell Hole Reservoir hold?
Hell Hole Reservoir has a total capacity of 255 hm³.
Where is Hell Hole Reservoir reservoir located?
Hell Hole Reservoir is located in California, United States, within the California basin (coordinates 39.058°N, 120.407°W).
What is Hell Hole Reservoir used for?
Hell Hole Reservoir is used primarily for multiple purposes, and is managed by CDEC.