Not sure if this sounds reasonable, but I think the 8 year old gas water heater in the place I just moved into last month is using more gas than it should be.
Gas meter recorded 50 therms used last month which seems like twice as much as a 50gal 38,000 BTU water heater should be using (the tag on it estimates 258 therms anually, i.e. 21.5/month).
There doesn't seem to be an obvious leak anywhere. None of the exposed gas lines, (including exterior lines) are leaking. Both me and a tech from the gas company did a bubble test when he was here for the initial inspection upon move in. I've also tested by turning everything off and monitored the meter after a few hours, and it didn't move.
The only thing that has been running is a water heater and a dryer, everything else has is powered off and has the valve shut off to it (pool heater, bbq, furnace). The dryer I brought in from my last place, and has been operating as usual. It's only been run for about 2.5 hours in a month.
Other than the water heater leaking somewhere besides an exposed gas line/nut (I haven't detected a smell), I'm not sure what could be causing the excessive gas usage. Can they use more gas as they get older and start to fail?
Any ideas on other obvious things to check or will I need a plumber to narrow this one down?