Community Warning System

Active Alerts

View active alerts at CWS Alerts or on the CWS Twitter 

Community Warning System Siren Test Schedule

  • First Wednesday of every month at 11:00 am: the Community Warning System Siren Test (County wide) - Sirens sound for less than 3 minutes, re-sound during an emergency
  • Every Wednesday at approximately 11:00 am: the Community Warning System GROWL test (County wide - a few second barely audible test of the system

Additional Warning System Test Schedule

  • Every Monday at 09:00 am: Chevron In Plant Evacuation Test (Internal) - Sirens sound for less than 3 minutes, re-sound during an emergency
  • Every Wednesday at 11:00 am: Chevron Refinery Alert Test (Internal) - Sirens sound for less than 3 minutes, re-sound during an emergency

Cell Phone Alerts Now Available!


The Community Warning System (CWS) is an emergency warning system that consists of alert, notification, education. The alert and notification features are linked by a radio frequency network, and are designed to function when telephone systems fail. Signals carried by radio frequency activate every part of the emergency system.

The system's design features multiple safe guards such as back-up power at each broadcast point, operation on multiple radio frequencies, and four broadcast towers within the county to receive and broadcast signals so that there is an excellent chance that the system will survive an earthquake.

The Contra Costa County Community Warning System was designed, installed, and is being maintained by Alerting Solutions, Inc. from Martinez, California.  

Mission Statement

Our mission is to provide an alert and notification system that is able to:
  • Immediately alert adjacent residents (one mile radius) to shelter-in-place in response to an emergency that may be harmful to their well being
  • Notify appropriate emergency response agencies concerning the emergency
  • Provide on-going updates about the incident and additional protective measures that may be required

Vision Statement

Our vision is to have in place an emergency alert and notification system infrastructure that is capable of providing emergency notification throughout Contra Costa County by means of radio and television (including cable stations). This vision will assure that Contra Costa County is able to immediately notify its community that an emergency has occurred and to communicate accurate protective action information for individual safety.

Guiding Principles
  • Recognize that people's safety during an emergency is the highest priority
  • Implement an alert and emergency notification system to reduce adverse impact for individuals affected during an emergency situation
  • Foster an awareness of the alert and notification system throughout the county, and provide support for on-going education about "Shelter-In-Place" emergency measures
  • Implement project in phases: Phase I to be funded by a broad base of industries, and Phase 2 and all additional phases to be funded by public and other community agencies
  • Gift the project to Contra Costa County at the completion of Phase I implementation 


Contra Costa County Community Awareness & Emergency Response (CAER)

For more information, please visit CAER's website.

Contact Information

If you have questions, contact:
440 Civic Center Plaza
Attn: Office of Emergency Services
Richmond, CA 94804
510-620-6866 (Non-Emergency Phone Number)