Mallacomes
Mallacomes is an earth dam located in Sonoma County, California, built in 1951. It carries a High hazard potential classification and has a satisfactory condition assessment.
About Mallacomes
The primary purpose of Mallacomes 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 Knights Valley California, Llc (private). It impounds the Foote Creek near Healdsburg.
The dam stands 57 feet tall and stretches 940 feet across, creates a reservoir covering 12 acres, has a maximum storage capacity of 225 acre-feet, and collects water from a drainage area of 1 square miles. Completed in 1951, 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 08/14/2025.
At 57 feet, this dam is taller than 95% 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 | Sonoma |
| Nearest City | Healdsburg |
| River/Stream | Foote Creek |
| Coordinates | 38.64470, -122.68090 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 57 ft |
| Dam Height | 57 ft |
| Dam Length | 940 ft |
| Year Completed | 1951 (75 years old) |
Storage & Hydraulics
| NID Storage | 225 acre-ft |
| Max Storage | 225 acre-ft |
| Surface Area | 12 acres |
| Drainage Area | 1 sq mi |
Ownership & Safety
| Purpose | Water Supply |
| Owner | Knights Valley California, LLC |
| Owner Type | Private |
| Hazard Classification | High |
| Condition Assessment | Satisfactory |
| Last Inspection | 08/14/2025 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | CA00591 |
| Federal ID | CA00591 |
| More Info | State Dam Safety Program |