Reservoir · California · United States · CDEC
Castaic Lake
94.1% full
Capacity
399.28 hm³
Volume stored
376 hm³
Coordinates
34.515°N, 118.610°W
Last updated
2026-08-03
Current fill
94.1%vs 7 days ago
-0.5%losing
vs 1 year ago
-1.1%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: 2026-08-03.
Catchment Weather
Past 30 days + 14-day forecast · Open-Meteo
Satellite imagery: Esri, Maxar, Earthstar Geographics. Map: Esri, HERE, Garmin, © OpenStreetMap contributors. 34.515, -118.610 · Open in Google Maps
About Castaic Lake
As of August 3, 2026, Castaic Lake is filled to 94.1% of its total capacity, holding roughly 376 hm³ of water out of a maximum 399 hm³. At this level the reservoir is high.
Over the most recent week on record the fill level has held broadly steady (-0.5 pts), and it is 1.1 points below its level on the same date a year earlier.
Across the readings we hold for Castaic Lake — 1823 data points between August 5, 2021 and August 3, 2026 — the level has ranged from a low of 27.0% (September 21, 2021) to a high of 100.2% (July 12, 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 34.515°N, 118.610°W.
Key facts
- Current fill level
- 94.1%
- Water stored
- 376 hm³
- Total capacity
- 399 hm³
- 7-day change
- ▼ 0.5 pts
- Year-on-year
- ▼ 1.1 pts
- Primary use
- Multipurpose
- River basin
- California
- Operator
- CDEC
- Coordinates
- 34.515°N, 118.610°W
- Last updated
- August 3, 2026
Recent readings
| Date | Fill level | Volume (hm³) |
|---|---|---|
| 3 Aug 2026 | 94.1% | 376 |
| 2 Aug 2026 | 94.3% | 377 |
| 1 Aug 2026 | 94.5% | 378 |
| 31 Jul 2026 | 94.7% | 378 |
| 30 Jul 2026 | 94.6% | 378 |
| 29 Jul 2026 | 94.5% | 378 |
| 28 Jul 2026 | 94.7% | 378 |
| 27 Jul 2026 | 94.6% | 378 |
| 26 Jul 2026 | 94.9% | 379 |
| 25 Jul 2026 | 95.0% | 379 |
| 24 Jul 2026 | 95.1% | 380 |
| 23 Jul 2026 | 94.8% | 379 |
Frequently asked questions
What is the current water level of Castaic Lake?
As of August 3, 2026, Castaic Lake is at 94.1% of its capacity, holding approximately 376 hm³ of water, according to CDEC (CA DWR) data.
Is Castaic Lake reservoir full?
No. As of August 3, 2026, Castaic Lake is high at 94.1% of its capacity, so it is not full.
Is the water level at Castaic Lake rising or falling?
The level at Castaic Lake has been broadly stable over the latest week on record (-0.5 points).
How much water can Castaic Lake hold?
Castaic Lake has a total capacity of 399 hm³.
Where is Castaic Lake reservoir located?
Castaic Lake is located in California, United States, within the California basin (coordinates 34.515°N, 118.610°W).
What is Castaic Lake used for?
Castaic Lake is used primarily for multiple purposes, and is managed by CDEC.