Pour some antifreeze into the traps. Otherwise I always blow out the water with a tire inflator, takes about 15 minutes. Make sure to open the drains under the trailer and turn on the pump to run it out of water. Since we use our TT year around, had to re-winterize 3 times, no biggy. Or keep the heat on to 50 as suggested. Have been doing this for years, never froze any pipes. Started that after I first used antifreeze and didn't like cleaning it out of the system and it changed the taste of the water for a while.