<!-- canonical: https://the-waterline.com/basin/san-joaquin -->
<!-- Machine-readable Markdown for agents. Append .md to any page URL; index at https://the-waterline.com/llms.txt -->

# San Joaquin basin

Reservoir storage across California

_Data through Aug 12, 2026 · source last checked Aug 13, 2026 · page revised Aug 13, 2026_

> Now 1.86M af, 6% below the 5-yr median.

San Joaquin basin storage fell to 1.87M af, down 1.3% on the week. The basin is 6% below its 5-year median. Month-over-month storage declined 8.4%, tracking the ongoing summer drawdown.

## The numbers

| Period | Current | Prior | Change |
| --- | --- | --- | --- |
| Week over week | 1.86M af | 1.88M af | -1.2% |
| Month over month | 1.86M af | 2.02M af | -8.0% |
| Year over year | 1.86M af | 1.97M af | -5.7% |
| vs 5-yr median | 1.86M af | 1.97M af | -5.7% |

## About this data

- Source: US Bureau of Reclamation RISE; California reservoirs via CA DWR CDEC
- Series: Reservoir storage summed across the basin
- Geography: San Joaquin basin
- Unit: acre-feet
- Calculation period: Daily reading
- Last observation: Aug 12, 2026
- Update frequency: Daily

---
Cite: San Joaquin basin storage is 6% below its 5-yr median. The Waterline, data through Aug 12, 2026. https://the-waterline.com/basin/san-joaquin
Canonical URL: https://the-waterline.com/basin/san-joaquin