Orange County Reservoir is an earth dam located in Orange County, California, built in 1941. It carries a Low hazard potential classification and has a satisfactory condition assessment.
Dam profile
NID height · 103 ft103 ft tall and 655 ft long, taller than 98% of U.S. dams with a recorded height. Height is drawn to scale against a ten-story building, about 100 ft; the profile is a generic embankment section and the water level is illustrative.
About Orange County Reservoir
The primary purpose of Orange County 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 Metropolitan Water District of Southern California (public utility). It impounds the Tr Fullerton Cr.
The dam stands 103 feet tall and stretches 655 feet across, creates a reservoir covering 7 acres, has a maximum storage capacity of 217 acre-feet, and collects water from a drainage area of 0 square miles. Completed in 1941, the structure is well-established, with more than 75 years of service.
This dam has a low hazard potential classification, meaning that failure would cause minimal damage, limited primarily to the dam owner's property, with no expected loss of life. 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 08/13/2025.
At 103 feet, this dam is taller than 98% of all dams in the United States.
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Location
| State | California |
| County | Orange |
| River/Stream | Tr Fullerton Cr |
| Coordinates | 33.93670, -117.88420 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 103 ft |
| Dam Height | 103 ft |
| Dam Length | 655 ft |
| Year Completed | 1941 (85 years old) |
Storage & Hydraulics
| NID Storage | 217 acre-ft |
| Max Storage | 217 acre-ft |
| Surface Area | 7 acres |
| Drainage Area | 0 sq mi |
Ownership & Safety
| Purpose | Water Supply |
| Owner | Metropolitan Water District of Southern California |
| Owner Type | Public Utility |
| Hazard Classification | Low |
| Condition Assessment | Satisfactory |
| Last Inspection | 08/13/2025 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | CA00218 |
| Federal ID | CA00218 |
| More Info | State Dam Safety Program |