Ler Crystal Springs
Ler Crystal Springs is a gravity dam located in San Mateo County, California, built in 1888. It carries a High hazard potential classification and has a satisfactory condition assessment.
About Ler Crystal Springs
The primary purpose of Ler Crystal Springs 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 And County Of San Francisco (local government). It impounds the San Mateo Creek near San Mateo.
The dam stands 149 feet tall and stretches 600 feet across, creates a reservoir covering 1,323 acres, has a maximum storage capacity of 57,910 acre-feet, and collects water from a drainage area of 28 square miles. Completed in 1888, the structure is over a century 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 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 11/20/2024.
At 149 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 Mateo |
| Nearest City | San Mateo |
| River/Stream | San Mateo Creek |
| Coordinates | 37.52830, -122.36160 |
Physical Characteristics
| Dam Type | Gravity |
| NID Height | 149 ft |
| Dam Height | 149 ft |
| Dam Length | 600 ft |
| Year Completed | 1888 (138 years old) |
Storage & Hydraulics
| NID Storage | 57,910 acre-ft |
| Max Storage | 57,910 acre-ft |
| Surface Area | 1,323 acres |
| Drainage Area | 28 sq mi |
Ownership & Safety
| Purpose | Water Supply |
| Owner | City and County of San Francisco |
| Owner Type | Local Government |
| Hazard Classification | High |
| Condition Assessment | Satisfactory |
| Last Inspection | 11/20/2024 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | CA00127 |
| Federal ID | CA00127 |
| More Info | State Dam Safety Program |