Added a couple extra drain valves on all the water lines. Think I got about ten of them. Open them all up, last thing do to leaving camp. Get home air pressure regulater set at 75 psi. Takes about 5 minutes. Nothing left to blow out. One by one turn all the valves open then close , starting closest to the city pressure hookup of to the farshest one away. Do it again. Done. Gallon of rv antifreeze in all the p-trap drains. Probably go out a couple more times. Do it all over again.