I was recently asked how we keep our pipes in the trailer from freezing in the winter. Our first winter in the camper saw several stretches of nights in the teens, and that is when we figured out what to do. We woke up one morning to no water. We had wrapped the exposed cold water pipes with closed cell styrofoam pipe insulation (it can get wet and doesn’t lose it’s insulative properties). It comes in long “sticks” and already has a slit cut down the length. We first put on a 1/2 inch piece and then layered a 1 inch piece over that. We duct taped it closed and it worked well enough down into the upper 20’s, but froze when it hit the first stretch in the teens. We then added plastic encased insulation over the whole thing and taped it on. This insulation comes in boxes that are shipped with dry ice in them. It is thrown away at work, so we save it up and use it for many things (the plastic allows it to get wet). Our water heater is in our container, so there is a pipe running out the bottom of it, under the ground same as above, and up underneath the camper. It is wrapped in the closed cell pipe insulation and then fed through corrugated plastic pipe. We then filled the corrugated pipe with great stuff and duct taped it all. The pipes that are underground aren’t very deep (we dug the ditch with a shovel, not a trencher) and we piled mulch on top of the dirt after filling it in, just for an little extra mass to keep them warmer. The pipes underneath the camper aren’t accessible because they are (supposed to be) covered with a liner that spans the whole trailer. We have not had any trouble with these…BUT take into account we live in Alabama where we never get lower than the teens, for short periods of time, and we leave the water dripping on those nights. There is also a compartment under the bunk beds that is storage accessed from outside and we put insulation in there on its “ceiling” because some of our pipes run through there.