Reservoir · Montana · United States · BOR RISE
Helena Valley Reservoir and Dam
91.8% full
Capacity
12.89 hm³
Volume stored
12 hm³
Coordinates
46.638°N, 111.882°W
Last updated
2026-07-28
Current fill
91.8%vs 7 days ago
-0.1%losing
vs 1 year ago
-1.0%year-over-year
7-day trend
→stable
Data source: BOR RISE — US Bureau of Reclamation — 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: 2026-07-28.
Catchment Weather
Past 30 days + 14-day forecast · Open-Meteo
Satellite imagery: Esri, Maxar, Earthstar Geographics. Map: Esri, HERE, Garmin, © OpenStreetMap contributors. 46.638, -111.882 · Open in Google Maps
About Helena Valley Reservoir and Dam
As of July 28, 2026, Helena Valley Reservoir and Dam is filled to 91.8% of its total capacity, holding roughly 12 hm³ of water out of a maximum 13 hm³. At this level the reservoir is high.
Over the most recent week on record the fill level has held broadly steady (-0.1 pts), and it is 1.0 points below its level on the same date a year earlier.
Across the readings we hold for Helena Valley Reservoir and Dam — 1823 data points between July 31, 2021 and July 28, 2026 — the level has ranged from a low of 60.6% (April 15, 2025) to a high of 99.7% (July 2, 2023). On average the reservoir is fullest around May and at its lowest around March.
It is operated by BOR primarily for multiple purposes. It lies within the Montana basin at 46.638°N, 111.882°W.
Key facts
- Current fill level
- 91.8%
- Water stored
- 12 hm³
- Total capacity
- 13 hm³
- 7-day change
- ▼ 0.1 pts
- Year-on-year
- ▼ 1.0 pts
- Primary use
- Multipurpose
- River basin
- Montana
- Operator
- BOR
- Coordinates
- 46.638°N, 111.882°W
- Last updated
- July 28, 2026
Recent readings
| Date | Fill level | Volume (hm³) |
|---|---|---|
| 28 Jul 2026 | 91.8% | 12 |
| 27 Jul 2026 | 91.9% | 12 |
| 26 Jul 2026 | 92.0% | 12 |
| 25 Jul 2026 | 92.1% | 12 |
| 24 Jul 2026 | 92.2% | 12 |
| 23 Jul 2026 | 92.6% | 12 |
| 22 Jul 2026 | 93.5% | 12 |
| 21 Jul 2026 | 94.5% | 12 |
| 20 Jul 2026 | 95.5% | 12 |
| 19 Jul 2026 | 96.5% | 12 |
| 18 Jul 2026 | 97.3% | 13 |
| 17 Jul 2026 | 97.8% | 13 |
Frequently asked questions
What is the current water level of Helena Valley Reservoir and Dam?
As of July 28, 2026, Helena Valley Reservoir and Dam is at 91.8% of its capacity, holding approximately 12 hm³ of water, according to BOR RISE (US Bureau of Reclamation) data.
Is Helena Valley Reservoir and Dam reservoir full?
No. As of July 28, 2026, Helena Valley Reservoir and Dam is high at 91.8% of its capacity, so it is not full.
Is the water level at Helena Valley Reservoir and Dam rising or falling?
The level at Helena Valley Reservoir and Dam has been broadly stable over the latest week on record (-0.1 points).
How much water can Helena Valley Reservoir and Dam hold?
Helena Valley Reservoir and Dam has a total capacity of 13 hm³.
Where is Helena Valley Reservoir and Dam reservoir located?
Helena Valley Reservoir and Dam is located in Montana, United States, within the Montana basin (coordinates 46.638°N, 111.882°W).
What is Helena Valley Reservoir and Dam used for?
Helena Valley Reservoir and Dam is used primarily for multiple purposes, and is managed by BOR.