The City and County of San Francisco is investing in upgrades to the aging Outdoor Public Warning System (OPWS). The siren system will be out of service during the two-year upgrade project. The upgrades include a new operating system, stronger encryption and hardware that will improve the reliability and security of the siren system.

Shutdown Date: Wednesday, December 11, 2019

Project Timeline: Estimated up to two (2) years

Estimated Budget: $2,000,000 to $2,500,000

During the OPWS upgrade, San Franciscans are encouraged to sign up for AlertSF which is San Francisco’s emergency text message system. People can simply text their zip code to 888-777 or visit www.alertsf.org to register. AlertSF issues alerts and instructions by text message or email following a natural disaster, major police, fire, health emergencies or significant transportation disruptions.

General Questions

Q: What is the Outdoor Public Warning System and how does it work?

A: The Outdoor Public Warning System (OPWS) is a system of 119 sirens located throughout San Francisco. The purpose of the alarm system is to alert residents and visitors about critical life-safety emergencies like a tsunami, contaminated water supply or radiological attack.



In the event of an emergency, a 15 second tone will sound repeatedly for five minutes with audible instructions. If for any reason you cannot understand or hear the message being emitted over the alarm, tune into local news and radio stations, go online to www.sf72.org or a local news source or follow us on Twitter @SF_Emergency for further information and updates.

The San Francisco Department of Technology (DT) provides maintenance of the system. The San Francisco Department of Emergency Management (DEM) may utilize the system to send out alerts and warnings for critical life and safety incidents.

The last real-event use of the OPWS was on Treasure Island in 2012 due to potential water contamination on the island caused by a water main break.



Q: Why are the Sirens being taken out of service?

A: A prepared and resilient San Francisco means ensuring we have reliable and secure alert and warning systems. The City and County of San Francisco is investing in upgrades to the antiquated OPWS to ensure the sirens can issue timely and reliable public alerts and warnings. The upgrades include new hardware that will improve the reliability and security of the siren system. Because of the upgrades, OPWS will be offline for up to two years. The last major upgrade of OPWS was in 2005.



OPWS Project Upgrade Questions

Q: What upgrades are being made to the system?

A: The City and County of San Francisco is investing in upgrades to the antiquated OPWS. The upgrades include new hardware that will improve the reliability and security of the siren system.



Q: Why will this take two years?

A: This project could take up to two years. The Department of Technology (DT) anticipates a shorter timeline, but it is often the case that this DT must reprioritize work as new tasks arise. A delay past the anticipated upgrade timeline would not be acceptable. So we are estimating the worst case scenario, with the understanding that we may not be operating in worst case circumstances.

Q: Why not do a staged roll-out?

A: San Francisco is performing this upgrade because a security vulnerability exists. Last year, DT implemented a short-term fix. Performing this upgrade will allow us to make the long-term investment needed to harden the system. The last upgrade to the Outdoor Public Warning System was in 2005. We believe it’s time for an update.

Q: If we can do without the system for two years, is it a good use of our money to upgrade it?

A: We believe in a system with redundancy and the sirens are one of many resources used to alert the public. Other resources include text, e-mail and voicecall alerts, Wireless Emergency Alerts, the Emergency Alert System and the deployment of first responders and other emergency workers.

Q: When will you share the details of the project upgrade timeline?

A: We are in the process of collecting those details. We need to collect an inventory of what work needs to be performed on each of the sirens. Some of this work may require us to order specialized equipment. This is not an over-the-air update. It requires us to deploy an engineer to each individual siren. After performing the work, we know that we must also test the system and fix any problems that may arise during the test period. Our estimated timeline takes into account all of this and leaves room for the unknown. What we know now is that we will turn the sirens off on Tuesday, December 10.

Q: How much will the project cost?

A: Upgrades to improve the reliability and security of the siren system will cost up to $2,500,000.