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Community Warning System

Contra Costa County Community Warning System

The County’s Community Warning System is designed to notify the public in case of toxic spills, floods, fires and other disasters. There are sirens installed near plants from Oakley to Richmond. They are clearly audible one mile away from the plants signaling people to go inside and listen to the radio and television for instructions. Money for the system was raised by voluntary contributions from industry and water treatment and wastewater treatment plants that handle hazardous chemicals. The system is operated by the County.

Emergency officials use a number of tools to alert you, including radio and TV, phone calls from the TENS (computerized telephone system that warns residents of a problem in their area) and the public can register for cell and pager email alerts at You can also buy a weather radio and program it to receive the emergency alerts. Instructions can be found here.

Siren testing is scheduled for the first Wednesday of each month at 11:00 a.m. For more information about the “Shelter, Shut & Listen” response, call (925) 313-9622.

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