We winter camped in the Poconos for a number of years. Had our RV on a permanent site. The water at the site was turned off, so no water ran through out water pipes, which we had drained before the cold weather hit. We also made certain all plugs were left open. We did use the drains of the sinks, and also the toilet (used gallon bottles of water to flush). At the end of each weekend, we would dump at our sewered site, and after closing the levers drop a gallon of cheap windshield washer fluid down each drain and the toilet to protect the levers from freezing shut. It worked perfectly. We would never leave any chance for water to freeze in the pipes. We used a large 60 cup coffee maker for our hot water and a 2.5 gallon plastic jug with a petcock on it for our cold water needs. Worked like a charm.
