Diemer No. 8
Diemer No. 8 is an other dam located in Orange County, California, built in 1968. It carries a Significant hazard potential classification and has a satisfactory condition assessment.
About Diemer No. 8
The primary purpose of Diemer No. 8 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 Offstream.
The dam stands 172 feet tall and stretches 1,004 feet across, creates a reservoir covering 1 acres, has a maximum storage capacity of 18 acre-feet, and collects water from a drainage area of 0 square miles. Completed in 1968, the structure is well into its service life at over 50 years old.
This dam has a significant hazard potential classification, meaning that a failure could cause significant economic damage — flooding roads, bridges, or property downstream — but is not expected to result in 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 172 feet, this dam is taller than 99% of all dams in the United States.
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Location
| State | California |
| County | Orange |
| River/Stream | Offstream |
| Coordinates | 33.91340, -117.82250 |
Physical Characteristics
| Dam Type | Other |
| NID Height | 172 ft |
| Dam Height | 172 ft |
| Dam Length | 1,004 ft |
| Year Completed | 1968 (58 years old) |
Storage & Hydraulics
| NID Storage | 18 acre-ft |
| Max Storage | 18 acre-ft |
| Surface Area | 1 acres |
| Drainage Area | 0 sq mi |
Ownership & Safety
| Purpose | Water Supply |
| Owner | Metropolitan Water District Of Southern California |
| Owner Type | Public Utility |
| Hazard Classification | Significant |
| Condition Assessment | Satisfactory |
| Last Inspection | 08/13/2025 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | CA00220 |
| Federal ID | CA00220 |
| More Info | State Dam Safety Program |