Santiago Creek
Santiago Creek is an earth dam located in Orange County, California, built in 1933. It carries a High hazard potential classification and has a poor condition assessment.
About Santiago Creek
The primary purpose of Santiago 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 Irvine Ranch Water District (public utility). It impounds the Santiago Creek near Orange.
The dam stands 136 feet tall and stretches 1,425 feet across, creates a reservoir covering 650 acres, has a maximum storage capacity of 25,000 acre-feet, and collects water from a drainage area of 63 square miles. Completed in 1933, the structure is well-established, with more than 75 years of service.
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 poor, meaning the dam has recognized safety deficiencies that require remediation to address risks. An emergency action plan is in place for this dam. The most recent inspection on record was 05/06/2025.
At 136 feet, this dam is taller than 99% 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 | Orange |
| Nearest City | Orange |
| River/Stream | Santiago Creek |
| Coordinates | 33.78630, -117.72260 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 136 ft |
| Dam Height | 136 ft |
| Dam Length | 1,425 ft |
| Year Completed | 1933 (93 years old) |
Storage & Hydraulics
| NID Storage | 25,000 acre-ft |
| Max Storage | 25,000 acre-ft |
| Surface Area | 650 acres |
| Drainage Area | 63 sq mi |
Ownership & Safety
| Purpose | Water Supply |
| Owner | Irvine Ranch Water District |
| Owner Type | Public Utility |
| Hazard Classification | High |
| Condition Assessment | Poor |
| Last Inspection | 05/06/2025 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | CA00298 |
| Federal ID | CA00298 |
| More Info | State Dam Safety Program |