water trickling will freeze in sewer hose. You really do not want that to happen. Believe me! We spend a freezing couple of months in Branson. We (and the campground) had a heat tape on the faucet and water hose, with insulation around it. Put clamp-on reflectors with 60 watt bulbs in the wet bins, along with a remote thermometer that we bought for the purpose. With outside temps down in the 20s, temp in bins stayed 40 and above. Electric heaters and built-in gas heat kept us comfortable. Dumped tanks as necessary, and kept valves closed.