There are many sites that recommend an earthquake safety valve to be installed on a gas line but they also sell service of installing so seems like they are just selling their service. Considering that there are moving parts in an earthquake valve what is the expected life of an earthquake safety valve and how frequently it should be tested?
Interesting that some services propose charging in the thousands per install but many plumbers will do for around $350 including parts and labor. This article written in 95 indicates they will install for $75 but some charge 200.
https://www.latimes.com/archives/la-xpm-1992-08-12-vw-5418-story.html
Looks like gas co does not recommend them because not everyone knows how to reset the valve and relight their water heaters so it is a logistical issue when an earthquake hits for the gas company to restore everyone's gas.
