Reservoir · California · United States · CDEC
ISB
50.6% full
Capacity
700.62 hm³
Volume stored
354 hm³
Coordinates
35.646°N, 118.473°W
Last updated
2026-07-08
Current fill
50.6%vs 7 days ago
-0.5%losing
vs 1 year ago
-15.2%year-over-year
7-day trend
→stable
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: 2026-07-08.
Catchment Weather
Past 30 days + 14-day forecast · Open-Meteo
Satellite imagery: Esri, Maxar, Earthstar Geographics. Map: Esri, HERE, Garmin, © OpenStreetMap contributors. 35.646, -118.473 · Open in Google Maps
About ISB
As of July 8, 2026, ISB is filled to 50.6% of its total capacity, holding roughly 354 hm³ of water out of a maximum 701 hm³. At this level the reservoir is within its normal operating range.
Over the most recent week on record the fill level has held broadly steady (-0.5 pts), and it is 15.2 points below its level on the same date a year earlier.
Across the readings we hold for ISB — 1824 data points between July 10, 2021 and July 8, 2026 — the level has ranged from a low of 6.4% (October 27, 2022) to a high of 96.8% (July 23, 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 35.646°N, 118.473°W.
Key facts
- Current fill level
- 50.6%
- Water stored
- 354 hm³
- Total capacity
- 701 hm³
- 7-day change
- ▼ 0.5 pts
- Year-on-year
- ▼ 15.2 pts
- Primary use
- Multipurpose
- River basin
- California
- Operator
- CDEC
- Coordinates
- 35.646°N, 118.473°W
- Last updated
- July 8, 2026
Recent readings
| Date | Fill level | Volume (hm³) |
|---|---|---|
| 8 Jul 2026 | 50.6% | 354 |
| 7 Jul 2026 | 51.1% | 358 |
| 6 Jul 2026 | 51.6% | 362 |
| 5 Jul 2026 | 52.1% | 365 |
| 4 Jul 2026 | 52.6% | 369 |
| 3 Jul 2026 | 53.1% | 372 |
| 2 Jul 2026 | 53.7% | 376 |
| 1 Jul 2026 | 54.2% | 380 |
| 30 Jun 2026 | 54.7% | 383 |
| 29 Jun 2026 | 55.2% | 387 |
| 28 Jun 2026 | 55.7% | 390 |
| 27 Jun 2026 | 56.2% | 393 |
Frequently asked questions
What is the current water level of ISB?
As of July 8, 2026, ISB is at 50.6% of its capacity, holding approximately 354 hm³ of water, according to CDEC (CA DWR) data.
Is ISB reservoir full?
No. As of July 8, 2026, ISB is within its normal operating range at 50.6% of its capacity, so it is not full.
Is the water level at ISB rising or falling?
The level at ISB has been broadly stable over the latest week on record (-0.5 points).
How much water can ISB hold?
ISB has a total capacity of 701 hm³.
Where is ISB reservoir located?
ISB is located in California, United States, within the California basin (coordinates 35.646°N, 118.473°W).
What is ISB used for?
ISB is used primarily for multiple purposes, and is managed by CDEC.