San Marcos
San Marcos is an arch dam located in San Diego County, California, built in 1946. It carries a High hazard potential classification and has a satisfactory condition assessment.
About San Marcos
San Marcos is a dam in San Diego, California. The dam is owned by Citizens Development Corporation (private). It impounds the San Marcos Creek near N/a.
The dam stands 52 feet tall and stretches 290 feet across, creates a reservoir covering 54 acres, has a maximum storage capacity of 480 acre-feet, and collects water from a drainage area of 29 square miles. Completed in 1946, 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 satisfactory, indicating no existing or potential dam safety deficiencies are recognized. An emergency action plan is in place for this dam. The most recent inspection on record was 08/22/2024.
At 52 feet, this dam is taller than 93% of dams nationwide.
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 | N/a |
| River/Stream | San Marcos Creek |
| Coordinates | 33.10920, -117.20910 |
Physical Characteristics
| Dam Type | Arch |
| NID Height | 52 ft |
| Dam Height | 52 ft |
| Dam Length | 290 ft |
| Year Completed | 1946 (80 years old) |
Storage & Hydraulics
| NID Storage | 480 acre-ft |
| Max Storage | 480 acre-ft |
| Surface Area | 54 acres |
| Drainage Area | 29 sq mi |
Ownership & Safety
| Purpose | Other |
| Owner | Citizens Development Corporation |
| Owner Type | Private |
| Hazard Classification | High |
| Condition Assessment | Satisfactory |
| Last Inspection | 08/22/2024 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | CA00782 |
| Federal ID | CA00782 |
| More Info | State Dam Safety Program |