Should you smell any gas from the regulator sitting on the tank if nothing is burning other than the pilot light on the water heater? I wonder if I have a faulty regulator. I opened the lid and got a distinct whiff. The gas amount has dropped significantly this winter, but it is winter and I have burned the central heat, Dearborn space heater, and the normal stove and water heater operation. Since it was filled in November it has dropped from 80% to 48% on a 500 gallon tank. It hasn't been a horrible winter in Texas (not like last year), and the house has spray foam insulation in the attic and under the floor joists. It is an old farm house that breathes.