Jerry,
The last time we had an outrageous electric bill I started thinking about where all the Kwhs were going to. With no electric heat (we have all natural gas stove, furnace, etc.) I thought that our submersible water pump was probably it. So I took the cover off the pressure switch and waited for it to stop. Well, it didn't. It turns out that there was a leak in the fitting right at the pump. It was originally installed with a cast iron fitting, which was nearly rusted away.
Mike