Castaic
Castaic is an earth dam located in Los Angeles County, California, built in 1973. It carries a High hazard potential classification and has a poor condition assessment.
About Castaic
The primary purpose of Castaic is water supply. The dam stores water for municipal, industrial, or agricultural use, helping ensure a reliable supply for the surrounding area. The dam is owned by California Department Of Water Resources (state). It impounds the Castaic Creek near Castaic.
The dam stands 340 feet tall and stretches 5,200 feet across, creates a reservoir covering 2,235 acres, has a maximum storage capacity of 323,700 acre-feet, and collects water from a drainage area of 153 square miles. Completed in 1973, the structure is well into its service life at over 50 years old.
This dam carries a high hazard potential classification, which means that a failure or uncontrolled release of water would likely cause loss of human life. This classification reflects the consequences of failure, not the likelihood — it indicates that people live or work in the area downstream. Its condition is rated poor, meaning the dam has recognized safety deficiencies that require remediation to address risks. An emergency action plan is in place for this dam. The most recent inspection on record was 10/07/2025.
At 340 feet, this dam is taller than 99% of all dams in the United States.
Living Downstream
If you live or work downstream of this dam, consider taking these steps: learn your local evacuation routes, check whether your county emergency management office has a dam failure inundation map, and sign up for local emergency alerts. The California dam safety program can provide more specific information about emergency planning for this structure.
Search for dams near your address to see all dams in your area with hazard classifications and safety data.
Location
| State | California |
| County | Los Angeles |
| Nearest City | Castaic |
| River/Stream | Castaic Creek |
| Coordinates | 34.52150, -118.61360 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 340 ft |
| Dam Height | 340 ft |
| Dam Length | 5,200 ft |
| Year Completed | 1973 (53 years old) |
Storage & Hydraulics
| NID Storage | 323,700 acre-ft |
| Max Storage | 323,700 acre-ft |
| Surface Area | 2,235 acres |
| Drainage Area | 153 sq mi |
Ownership & Safety
| Purpose | Water Supply |
| Owner | California Department of Water Resources |
| Owner Type | State |
| Hazard Classification | High |
| Condition Assessment | Poor |
| Last Inspection | 10/07/2025 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | CA00044 |
| Federal ID | CA00044 |
| More Info | State Dam Safety Program |