Seattle, WA Earthquake Safety: Seismic Gas Shutoff (2026)

Seismic gas shutoff valves are required in Washington state for buildings with building permits first issued on or after January 26, 1995. The valves must be installed downstream of the gas utility meter on the fuel gas piping in accordance with ANSI Z21.93-13/CSA 6.30-13 and the manufacturer's installation instructions. The Washington State Building Code Council has adopted these requirements as part of the state's fuel gas code. Seismic gas shutoff valves contain a sensor that detects significant ground motion (typically calibrated to 5.2 magnitude or greater earthquakes) and automatically closes the gas valve to prevent gas leaks that could cause fires or explosions after an earthquake. Installation must be performed by a licensed plumber or gas fitter. After activation, the valve must be manually reset by a qualified person who has confirmed there are no gas leaks. While not retroactively required for older buildings, Seattle seismic retrofit professionals strongly recommend installing shutoff valves on all buildings, especially those in liquefaction zones or near known fault lines. The valves cost approximately $300-$500 installed and provide significant protection against post-earthquake fire hazards.