Harold Reservoir
Harold Reservoir is an earth dam located in Los Angeles County, California, built in 1891. It carries a High hazard potential classification and has a satisfactory condition assessment.
About Harold Reservoir
The primary purpose of Harold Reservoir 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 Palmdale Water District (public utility). It impounds the Tr Antelope Val near Palmdale.
The dam stands 30 feet tall and stretches 2,800 feet across, creates a reservoir covering 218 acres, has a maximum storage capacity of 3,870 acre-feet, and collects water from a drainage area of 4 square miles. Completed in 1891, 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 05/01/2025.
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 | Los Angeles |
| Nearest City | Palmdale |
| River/Stream | Tr Antelope Val |
| Coordinates | 34.54610, -118.11150 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 30 ft |
| Dam Height | 30 ft |
| Dam Length | 2,800 ft |
| Year Completed | 1891 (135 years old) |
Storage & Hydraulics
| NID Storage | 3,870 acre-ft |
| Max Storage | 3,870 acre-ft |
| Surface Area | 218 acres |
| Drainage Area | 4 sq mi |
Ownership & Safety
| Purpose | Water Supply |
| Owner | Palmdale Water District |
| Owner Type | Public Utility |
| Hazard Classification | High |
| Condition Assessment | Satisfactory |
| Last Inspection | 05/01/2025 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | CA00238 |
| Federal ID | CA00238 |
| More Info | State Dam Safety Program |