Rattlesnake Canyon
Rattlesnake Canyon is an earth dam located in Orange County, California, built in 1959. It carries a High hazard potential classification and has a fair condition assessment.
About Rattlesnake Canyon
The primary purpose of Rattlesnake Canyon 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 Rattlesnake Canyon Wash near Northwood Point.
The dam stands 79 feet tall and stretches 980 feet across, creates a reservoir covering 60 acres, has a maximum storage capacity of 1,480 acre-feet, and collects water from a drainage area of 2 square miles. Completed in 1959, 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 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 05/07/2025.
At 79 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 | Orange |
| Nearest City | Northwood Point |
| River/Stream | Rattlesnake Canyon Wash |
| Coordinates | 33.72950, -117.74210 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 79 ft |
| Dam Height | 79 ft |
| Dam Length | 980 ft |
| Year Completed | 1959 (67 years old) |
Storage & Hydraulics
| NID Storage | 1,480 acre-ft |
| Max Storage | 1,480 acre-ft |
| Surface Area | 60 acres |
| Drainage Area | 2 sq mi |
Ownership & Safety
| Purpose | Water Supply |
| Owner | Irvine Ranch Water District |
| Owner Type | Public Utility |
| Hazard Classification | High |
| Condition Assessment | Fair |
| Last Inspection | 05/07/2025 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | CA00855 |
| Federal ID | CA00855 |
| More Info | State Dam Safety Program |