# Why are Western reservoir levels falling right now? 34.37M af across 20 tracked reservoirs as of Aug 25, 2026. Total storage has fallen 19 straight weeks. _Data through Aug 25, 2026 · source last checked Aug 27, 2026 · page revised Aug 27, 2026_ > Tracked-total storage has fallen 19 consecutive weeks, down 6.81M af (-16.5%) since Apr 13, 2026. 14% of California is in drought (D1-D4) or worse, up 7 points week over week (US Drought Monitor). Lake Mead storage is 20% below its 5-yr median for the date. The system is in the summer-fall drawdown, when irrigation and delivery releases typically exceed inflow. Tracked-total storage stands at 34.37M af, off 6.81M af (16.5%) since Apr 13 across 19 consecutive weeks of decline. Week over week storage fell 1.5%, with a 6.4% month-over-month drop as irrigation and delivery releases outpace inflow through the summer-fall drawdown. Fourteen percent of California is in drought (D1-D4) or worse per the US Drought Monitor, up 7 points week over week. Lake Mead storage is 20% below its 5-year median for the date. ## The numbers | Period | Current | Prior | Change | | --- | --- | --- | --- | | Week over week | 34.37M af | 34.89M af | -1.5% | | Month over month | 34.37M af | 36.74M af | -6.4% | | Year over year | 34.37M af | 39.13M af | -12.2% | | vs 5-yr median | 34.37M af | 39.13M af | -12.2% | ## What draws western reservoirs down Falling reservoir levels are, first of all, the normal shape of the western summer: the system is designed to draw down. Reservoirs bank spring snowmelt precisely so it can be released through the dry months, so a decline from July through October is the system working, and the question is whether the draw is running faster or deeper than normal for the date. The combined daily figure that question is asked of is the site's total for [western reservoir levels](/reservoir/tracked-total). Irrigation season is the biggest single draw. Farm deliveries dominate summer releases across the West, and municipal and industrial demand rides alongside; the [allocation pages](/allocation) show how much water the big projects promised, which is what the summer draw is delivering. Weak snowpack is the supply-side cause. A thin winter snowpack means the spring fill never fully happens, and the summer draw starts from a lower peak; the [snowpack pages](/snowpack) versus their 1991-2020 median are the earliest read on that, months before it shows up in storage. Drought compounds year over year. In a dry year, soils and aquifers absorb melt before it reaches a gauge, runoff efficiency drops, and reservoirs are asked to cover the gap between supply and promised deliveries; a multi-year drought draws storage down in stair-steps that a single wet winter may not repair. The [drought map](/drought) tracks the footprint week by week. Environmental and downstream obligations keep water moving. Rivers must keep flowing for fish, water quality and downstream rights holders, so releases continue even in dry years; those obligations put a floor under the draw that operators cannot simply shut off. Evaporation is the quiet loss. Large desert reservoirs lose meaningful water off their surface every hot month, a structural loss that grows with surface area and temperature and never shows up as a delivery to anyone. The [tracked-total page](/reservoir/tracked-total) carries the combined daily number this page's direction call is computed from, the [streamflow gauges](/streamflow) show what is still arriving, and the [rising twin of this page](/why/reservoir-levels-rising) covers the same system running the other way. ## About this data - Source: US Bureau of Reclamation RISE; California reservoirs via CA DWR CDEC - Series: Reservoir storage summed across the tracked set - Geography: The tracked major western reservoirs - Unit: acre-feet - Calculation period: Daily reading - Last observation: Aug 25, 2026 - Update frequency: Daily --- Cite: Combined storage across The Waterline's tracked western reservoirs is 12% below its 5-yr median for the date. The Waterline, data through Aug 25, 2026. https://the-waterline.com/why/reservoir-levels-falling Canonical URL: https://the-waterline.com/why/reservoir-levels-falling