Maloney
Maloney is an earth dam located in Contra Costa County, California, built in 1960. It carries a High hazard potential classification and has a satisfactory condition assessment.
About Maloney
The primary purpose of Maloney 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 East Bay Municipal Utility District (public utility). It impounds the Offstream.
The dam stands 107 feet tall and stretches 620 feet across, creates a reservoir covering 3 acres, and has a maximum storage capacity of 68 acre-feet. Completed in 1960, the structure is well into its service life at over 50 years 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 10/22/2024.
At 107 feet, this dam is taller than 98% 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 | Contra Costa |
| River/Stream | Offstream |
| Coordinates | 37.99800, -122.29800 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 107 ft |
| Dam Height | 107 ft |
| Dam Length | 620 ft |
| Year Completed | 1960 (66 years old) |
Storage & Hydraulics
| NID Storage | 68 acre-ft |
| Max Storage | 68 acre-ft |
| Surface Area | 3 acres |
Ownership & Safety
| Purpose | Water Supply |
| Owner | East Bay Municipal Utility District |
| Owner Type | Public Utility |
| Hazard Classification | High |
| Condition Assessment | Satisfactory |
| Last Inspection | 10/22/2024 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | CA00180 |
| Federal ID | CA00180 |
| More Info | State Dam Safety Program |