Reservoirs
Below normalWestern reservoir levels, total storage
34.02M af across the 21 major western reservoirs The Waterline tracks, as of Oct 15, 2026 (39% of combined capacity). One combined daily storage total.
Data through Oct 15, 2026 · source last checked Oct 17, 2026 · page revised Oct 17, 2026
Cite
- Total storage
About this data
- Source
- US Bureau of Reclamation RISE; California reservoirs via CA DWR CDEC
- Series
- End-of-day reservoir storage
- Geography
- Western reservoir levels, total
- Unit
- acre-feet
- Calculation
- Daily reading
- Last observation
- Oct 15, 2026
- Update frequency
- Daily
Now 34.02M af, 11% below the 5-yr median, 39% of combined capacity.
Storage across 21 major western reservoirs totaled 34.02M af, 11% below the 5-year median. Year-over-year the combined total fell 11.1%. Week-to-week change was negligible.
| Period | Current | Prior | Change |
|---|---|---|---|
| Week over week | 34.02M af | 34.11M af | -0.3% |
| Month over month | 34.02M af | 34.54M af | -1.5% |
| Year over year | 34.02M af | 38.27M af | -11.1% |
| vs 5-yr median | 34.02M af | 38.27M af | -11.1% |
| Basin | Reservoirs | Storage | Share of capacity | vs 5-yr median | As of |
|---|---|---|---|---|---|
| Gunnison-Colorado | Blue Mesa Reservoir | 139,818 af | 15% | -64% | Oct 15, 2026 |
| Colorado (Upper) | Lake Powell | 5.25M af | 22% | -27% | Oct 15, 2026 |
| Wind-Bighorn-Missouri | Boysen Reservoir | 504,275 af | 68% | -20% | Oct 15, 2026 |
| Rio Grande | Elephant Butte Reservoir | 94,701 af | 5% | -17% | Oct 15, 2026 |
| Colorado (Lower) | Lake Havasu, Lake Mead, Lake Mohave | 9M af | 32% | -16% | Oct 15, 2026 |
| Green-Colorado | Flaming Gorge Reservoir, Fontenelle Reservoir | 2.73M af | 68% | -15% | Oct 15, 2026 |
| Feather-Sacramento | Lake Oroville | 1.53M af | 45% | -14% | Oct 15, 2026 |
| San Juan-Colorado | Navajo Reservoir | 864,313 af | 51% | -9% | Oct 15, 2026 |
| Sacramento | Shasta Lake, Whiskeytown Lake | 2.61M af | 54% | -9% | Oct 15, 2026 |
| American-Sacramento | Folsom Lake | 401,070 af | 41% | -8% | Oct 15, 2026 |
| San Joaquin | Millerton Lake, New Melones Lake | 1.74M af | 60% | -7% | Oct 15, 2026 |
| Flathead-Columbia | Hungry Horse Reservoir | 3.06M af | 88% | -1% | Oct 15, 2026 |
| Missouri | Canyon Ferry Lake | 1.48M af | 78% | +1% | Oct 15, 2026 |
| Tuolumne-San Joaquin | New Don Pedro Reservoir | 1.51M af | 74% | +2% | Oct 15, 2026 |
| Trinity-Klamath | Trinity Lake | 1.65M af | 68% | +33% | Oct 15, 2026 |
| San Joaquin-Delta | San Luis Reservoir | 1.46M af | 71% | +38% | Oct 15, 2026 |
A basin with more than one tracked reservoir is summed on the days every one of them reports, then compared with the same sum's median for the date over up to five prior years. Share of capacity uses each reservoir's total capacity.
Previous weeks
An earlier week
Storage across 21 major western reservoirs totaled 34.02M af as of Oct 14, down 11.1% year-over-year and sitting 11% below the 5-year median. The combined total represents 39% of capacity.
An earlier week
Storage across the 21 major western reservoirs tracked here stands at 34.01M af, 11% below the 5-year median for mid-October and at 39% of combined capacity. The total is down 11.0% from a year ago. Week over week storage slipped 0.4%.
Week of Sep 30, 2026
Total storage across the 21 major western reservoirs stood at 34.21M af as of Sep 30, down 11.4% year over year. The level sits 11% below the 5-year median at 40% of combined capacity. Month over month storage fell 3.0%, with a week-over-week change of -0.4%.
Week of Sep 23, 2026
Western storage totaled 34.34M af as of Sep 23, down 11.6% from a year earlier. At 40% of combined capacity, the 21-reservoir total sat 12% below its 5-year median.
About this total
The 21 major western reservoirs The Waterline tracks hold 34.02 million acre-feet combined as of Oct 15, 2026, 39% of combined capacity and 11% below the 5-yr median. Measured against its own capacity, Elephant Butte Reservoir is the emptiest at 5% and Whiskeytown Lake the fullest at 98%.
This page adds up the reservoir levels The Waterline tracks, 21 of the West's major reservoirs including Lake Mead, Lake Powell, Hungry Horse Reservoir, Flaming Gorge Reservoir, into one combined daily storage total. It is the widest single read on how much water the tracked system is holding, compared to its own five-year median like every other page on the site. A day appears here only when every tracked reservoir reports it, so the total is always a true sum of the same set and a gap in one reservoir's feed never shows up as a system-wide swing. It is the total for this tracked set, not for every reservoir in the West: use it for the direction and scale of the system, the storage by basin table for the river systems behind a move, and the per-reservoir pages for the specific projects.
Common questions
What are Western reservoir levels right now?
The 21 major western reservoirs The Waterline tracks hold 34.02M af combined as of Oct 15, 2026, 39% of combined capacity, 11% below the 5-yr median. The chart above carries the daily total, and the per-reservoir pages carry each project's own level.
Are reservoir levels rising or falling?
Tracked-total storage has been broadly flat for 1 week, with no sustained move in either direction. The system is in the summer-fall drawdown, when irrigation and delivery releases typically exceed inflow.
Which reservoirs does this total cover?
The 21 major western reservoirs on this site, including Lake Mead, Lake Powell, Hungry Horse Reservoir, Flaming Gorge Reservoir. It is the total for this tracked set, not for every reservoir in the West, and a day appears in the total only when every member reports it. The reservoir section lists each one.
Where does this data come from?
Daily end-of-day storage readings from the US Bureau of Reclamation's RISE system, with California reservoirs from the state's CDEC network (CA DWR). The methodology page has the full sourcing.