El Capitan
El Capitan is an earth dam located in San Diego County, California, built in 1934. It carries a High hazard potential classification and has a poor condition assessment.
About El Capitan
The primary purpose of El Capitan 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 City Of San Diego (local government). It impounds the San Diego River near Lakeside.
The dam stands 237 feet tall and stretches 1,170 feet across, creates a reservoir covering 1,562 acres, has a maximum storage capacity of 112,800 acre-feet, and collects water from a drainage area of 188 square miles. Completed in 1934, the structure is well-established, with more than 75 years of service.
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 05/07/2025.
At 237 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 | San Diego |
| Nearest City | Lakeside |
| River/Stream | San Diego River |
| Coordinates | 32.88560, -116.80930 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 237 ft |
| Dam Height | 237 ft |
| Dam Length | 1,170 ft |
| Year Completed | 1934 (92 years old) |
Storage & Hydraulics
| NID Storage | 112,800 acre-ft |
| Max Storage | 112,800 acre-ft |
| Surface Area | 1,562 acres |
| Drainage Area | 188 sq mi |
| Max Discharge | 158,200 cfs |
Ownership & Safety
| Purpose | Water Supply |
| Owner | City of San Diego |
| Owner Type | Local Government |
| Hazard Classification | High |
| Condition Assessment | Poor |
| Last Inspection | 05/07/2025 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | CA00111 |
| Federal ID | CA00111 |
| More Info | State Dam Safety Program |