To blow out water, buy an air adapter for city water hookup, open both drains and all faucets including shower as well as prop open toilet flap, and water heater drain plug, then attach air hose and blow. Be aware that most compressors put out way too much pressure for trailer water lines, so never let air flow while valves/faucets are closed. Let it blow for a while to get all possible water out. Close the two drains while blowing, as they drain first. Let it blow for an hour or so. Remember to run the water pump for a few minutes while blowing to get water out of there, too. Finally, remove air hose, before closing faucets/valves.
