Mill Creek
Mill Creek is an earth dam located in Santa Cruz County, California, built in 1889. It carries a High hazard potential classification and has a fair condition assessment.
About Mill Creek
The primary purpose of Mill Creek 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 Lockheed Martin Space Systems Company (private). It impounds the Mill Creek near N/a.
The dam stands 76 feet tall and stretches 250 feet across, creates a reservoir covering 12 acres, has a maximum storage capacity of 223 acre-feet, and collects water from a drainage area of 0 square miles. Completed in 1889, 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 fair — the dam has minor deficiencies that are being addressed or do not pose an immediate safety threat. An emergency action plan is in place for this dam. The most recent inspection on record was 03/18/2025.
At 76 feet, this dam is taller than 97% 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 | Santa Cruz |
| Nearest City | N/a |
| River/Stream | Mill Creek |
| Coordinates | 37.11640, -122.21240 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 76 ft |
| Dam Height | 76 ft |
| Dam Length | 250 ft |
| Year Completed | 1889 (137 years old) |
Storage & Hydraulics
| NID Storage | 223 acre-ft |
| Max Storage | 223 acre-ft |
| Surface Area | 12 acres |
| Drainage Area | 0 sq mi |
Ownership & Safety
| Purpose | Water Supply |
| Owner | Lockheed Martin Space Systems Company |
| Owner Type | Private |
| Hazard Classification | High |
| Condition Assessment | Fair |
| Last Inspection | 03/18/2025 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | CA00688 |
| Federal ID | CA00688 |
| More Info | State Dam Safety Program |