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About the Community Alert Siren System

Made up of 50 strategically placed sirens throughout the local cities and counties within 10 miles of the plant, the Community Alert Siren System provides reliable, prompt notification to the general public to turn on their radio or television for important information from local authorities in the event of an emergency. While no longer needed to alert the public of an emergency at San Onofre due to its decommissioning, the community alert system remains in place to help notify residents of other types of emergencies as defined by the local cities and counties.

Should an event occur, residents in San Clement, Dana Point, San Juan Capistrano, Orange County and Camp Pendleton will hear a piercing siren that will sound steadily for three minutes at a time.

Jurisdictions are responsible for activating sirens in their community, not San Onofre. As a backup measure, Orange County has the ability to activate all sirens except for those at Camp Pendleton.

Along with the sirens, roving public address systems and/or messages to home, cell or business phones via AlertOC are also a signal to turn on a radio or television and wait for instructions.


If the sirens have been activated, turn on the television or the radio to KWVE FM 107.9 (Santa Ana) or KOGO AM 600 (San Diego).

An Emergency Alert System (EAS) message will be delivered by radio and TV. It may advise you to stay inside, evacuate the area, or do nothing depending on the nature of the emergency.


Southern California Edison (SCE) is responsible for maintaining and testing the siren system through June 30, 2019. Ensuring that all the sirens will work properly in a real emergency is a top priority. The regular testing of sirens includes:

  • Silent Tests – Tests the connections between the sirens and control centers.
  • Growl Tests – Brief audible test of each siren to ensure siren will sound.
  • Check your city's website for schedules for growl testing.


  • Check radio and TV stations. Also check your city's web-site and this site. If there is no message, there is no event.
  • Siren activation can only be done by your local jurisdictions. It is important to follow up with your city's Emergency Management Representative for more information. You can also follow us on Twitter.
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