San Andreas
Key Takeaway
San Andreas is classified as high hazard in California. It was completed in 1870 and is 156 years old. Its primary use is water supply. High hazard means loss of life is likely if the dam fails — it does not indicate the dam's current condition. Learn more.
Physical Details
| Dam Height | 107 ft (taller than 83.5% in CA) |
| Dam Length | 727 ft |
| Dam Type | Earth |
| Max Storage | 19.0K acre-ft |
| Surface Area | 550 acres |
| Drainage Area | 4 sq mi |
| Year Completed | 1870 (156 years old) |
| NID ID | CA00129 |
Safety Information
Loss of human life is likely if the dam fails.
Hazard potential describes downstream consequences of failure, not the dam's current condition. What does this mean?
Ownership
City and County of San Francisco
Local Government
Nearby Dams
Pilarcitos
San Mateo, CA
High Hazard 103 ftSpencer Lake
San Mateo, CA
High Hazard 87 ftCrocker
San Mateo, CA
High Hazard 45 ftLower Crystal Springs
San Mateo, CA
High Hazard 149 ftUpper Pond
San Mateo, CA
Significant Hazard 30 ftLaurel Creek
San Mateo, CA
High Hazard 40 ftCanada Road
San Mateo, CA
Low Hazard 52 ftMarina Lagoon
San Mateo, CA
Low Hazard 17 ftFrequently Asked Questions
What is the hazard classification of San Andreas?
San Andreas is classified as High Hazard. Loss of human life is likely if the dam fails. This classification refers to the potential downstream consequences of a failure, not the dam's current structural condition.
Who owns and operates San Andreas?
San Andreas is owned by City and County of San Francisco (Local Government). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.
When was San Andreas built?
San Andreas was completed in 1870, making it 156 years old. Many U.S. dams were built between the 1930s and 1970s during a period of major infrastructure investment.
What is the primary purpose of San Andreas?
San Andreas serves the following purposes: Water Supply. Many dams in the U.S. are multi-purpose, supporting flood control, water supply, recreation, and other uses.
How tall is San Andreas?
San Andreas has a dam height of 107 ft. Dam height is measured from the natural streambed at the downstream toe to the top of the dam, and may differ from the visible height.
When was San Andreas last inspected?
San Andreas was last inspected on November 2, 2022. Inspection dates indicate when a formal review occurred, not the results of that inspection.