San Antonio

About San Antonio

The primary purpose of San Antonio is flood risk reduction. The dam is designed to control downstream flooding by temporarily storing excess water during storms and releasing it at a controlled rate. The dam is owned by Monterey County Water Resources Agency (public utility). It impounds the San Antonio River near Bradley, San Ardo, Salinas.

The dam stands 202 feet tall and stretches 1,433 feet across, creates a reservoir covering 5,720 acres, has a maximum storage capacity of 350,000 acre-feet, and collects water from a drainage area of 353 square miles. Completed in 1965, 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 11/04/2025.

At 202 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.