Hello, Penny, I was not online over the weekend to respond to your request for information. As of now, in all the houses I have sold over the years in Los Angeles, Burbank and Glendale, the seller must almost always employ a retrofitter, before the close of escrow, to examine, among other things, whether a water heater is properly strapped (against earthquake damage), and whether it is properly vented. I cannot imagine a certificate of compliance being issued if a water heater were not properly vented to the outside; in fact, in many cases, following the '94 quake, many water heaters had to be moved to a metal cabinet outside the home, both in the interests of better ventialation, and in the interests of protecting the homeowner and his/her family after a quake. I hope this is of some help to you. Ron