Yesterday, we got our gas/electric bill only to discover that we had used 140 therms of gas last month. Our average is less than half that. In fact, we have never ever used anything close to that in the 3 years we've owned this house. I called PGE, she had me read the meter and we determined that in the week between the meter reading and today, our usage is back to normal levels. Thus, there doesn't seem to be a current gas leak anywhere that could explain it.

The only thing we did this month was have a new water heater installed. It was installed by a licensed plumber (reputable one we've used for years). It's the same size and model as the old one, only 20 years newer which should be more efficient. In the process, he also replaced all the surrounding plumbing including the gas line from the house to the unit.

Does anyone think it's possible that the plumber could have somehow blew through 70 therms of gas while installing the new heater? We called and asked and he said no, but really, what is he going to say?

Any other ideas on what could cause our gas to mysteriously double one month out of the blue, then return to normal? Our plan is to continue checking the meter weekly, but we are scratching our heads over what could have caused this!