The Community Warning System (CWS) issues alerts when available about situations in Contra Costa County that pose an imminent threat to life or health. The CWS is operated by the Office of the Sheriff in partnership with the county's Department of Health Services and its industry and public safety partners such as the San Ramon Valley Fire Protection District.

Alerts are sent as text, voice or email to registered users. Participants receive information for specific zip codes (selected during the registration process). To register, update, or deregister, visit the Contra Costa County Community Warning System website. Users can also receive text headlines via Twitter by following CoCoCWS.

If you have problems or questions about this service you can contact the Community Warning System by email at cws-staff@so.cccounty.us or by phone at (925) 313-9622.