Police Services
Alert Information
Although our district and its campuses have their own Campus Alert System (4CD Alert), there are a variety of other alert methods used to keep the public informed about emergencies or potential emergency situations in our county.
We have developed this page to provide you with access to these other systems and we encourage you to take full advantage of them.
Community Warning System (CWS)
Contra Costa County's Community Warning System (CWS) uses a variety of systems to alert the community to any imminent hazard to life or health. The CWS uses a variety of systems to reach the greatest number of people as quickly and reliably as possible, including:
- Sirens in special safety areas
- Telephone notification (wired and cellular)
- Broadcast radio and TV
- Cable television
- NOAA Weather Radio
CWS sirens may be heard in the communities of Richmond, San Pablo, Martinez, and Pittsburg. When activated for an actual incident,
the sirens indicate that community members should immediately Shelter-in-Place.
When the CWS is activated, emergency officials recommend tuning to KCBS 740 AM for emergency information.
If you have a television available, Bay Area television stations will also provide news reports, and should scroll information during the event.
Sirens are tested on the first Wednesday of every month at approximately 11:00 a.m.
Emergency Alert System
Contra Costa County is one of the first locations in the country to utilize National Weather Service radios to receive hazardous materials alerts.
In addition to receiving regional weather information, these radios are now available with technology that allows them to be programmed to receive
notifications for specific geographic locations. When activated for an actual emergency, specific instructions will be broadcast for the affected area.
To receive local Shelter-In-Place advisories, county residents should purchase a weather radio with Specific Area Message Encoding (SAME)
capability and program them as directed. Weather radios are readily available through electronic suppliers such as Radio Shack.
Like the Community Warning System (CWS), the Emergency Alert System (EAS) is tested every Wednesday at approximately 11:30 a.m.
For more information on this system or to obtain radio programming instructions, please visit the
Contra Costa County Community Awareness & Emergency Response (CAER) website.
Emergency Digital Information Service (EDIS)
The Emergency Digital Information Service (EDIS) delivers official information about emergencies and disasters to the public and the news
media in California. To view the latest EDIS bulletins, please visit the State of California OES EDIS website.
If you would like to receive automated e-mail messages on your computer or e-mail enabled pager via the EDIS system, please visit the EDIS
Providers page.
U.S. Homeland Security Advisory System
The U.S. Homeland Security Advisory System uses color-coded threat levels to communicate with public safety officials and the public.
The system identifies the threat level for a region (or regions) and the protective measures that may be implemented to reduce the
likelihood or impact of an attack.
To view the current threat level or learn more about this system, please visit the
United States Department of Homeland Security website.