Grant Lake
Grant Lake is an earth dam located in Mono County, California, built in 1940. It carries a High hazard potential classification and has a poor condition assessment.
About Grant Lake
The primary purpose of Grant Lake 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 Los Angeles Department Of Water And Power (local government). It impounds the Rush Creek near N/a.
The dam stands 87 feet tall and stretches 700 feet across, creates a reservoir covering 1,095 acres, has a maximum storage capacity of 47,525 acre-feet, and collects water from a drainage area of 60 square miles. Completed in 1940, 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 10/23/2024.
At 87 feet, this dam is taller than 97% 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 | Mono |
| Nearest City | N/a |
| River/Stream | Rush Creek |
| Coordinates | 37.86210, -119.10260 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 87 ft |
| Dam Height | 87 ft |
| Dam Length | 700 ft |
| Year Completed | 1940 (86 years old) |
Storage & Hydraulics
| NID Storage | 47,525 acre-ft |
| Max Storage | 47,525 acre-ft |
| Surface Area | 1,095 acres |
| Drainage Area | 60 sq mi |
Ownership & Safety
| Purpose | Water Supply |
| Owner | City of Los Angeles Department of Water and Power |
| Owner Type | Local Government |
| Hazard Classification | High |
| Condition Assessment | Poor |
| Last Inspection | 10/23/2024 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | CA00089 |
| Federal ID | CA00089 |
| More Info | State Dam Safety Program |