Don't kid yourself. An RV blade valve will freeze and come apart from freezing. Water will freeze and push the gasket out of wack causing the blade to leak (then crack from freezing water). We replaced one valve and rebuilt the other due to freezing temps in S GA. Redoing a black waste valve is such fun. Redoing the grey in only slightly less so. We will use the pvc ball valves and they will be inside an insulated bay that can be heated (all you need is a 60Watt incandescent light bulb). Lots of ways to heat the water bay. For all the other winters, we wrapped pipe heat cable (Frost King or Easy Heat brand) around the valves and built a temporary box out of pink or blue insulation sheathing. We put a small space heater plugged into a thermostat electric plug (Easy heat brand) and turned the heater on to low. When temps drop down to almost freezing, the heater will receive power and stay on until the exterior temps warm back above freezing. You can set an incandescent light bulb up on the same setup.
EasyHeat Pipe Heat Cable
EasyHeat Plug In Thermostat
Since we are heading into winter.....
The pipe heat cable can also be used on a water hose (laid flat -- do not spiral it) and covered with pipe insulation (use one size larger than your hose) and sealed shut with tape (the self sealing will not last). I like the neoprene
but that's costly. The cheaper foam
will work if you can cover it up well using water-resistant/weather resistant tape
. These winterized water hoses take up a lot of room when stored. So you may not want to do up a 25 ft hose if you do this. You need to allow enough "extra" heat cable on both ends to wrap the hose bibb (usually on the bibb itself not the pipe stand) and the city water hookup on the RV/Bus. These are the two vulnerable spots in the water system. I have a couple extra inches to loosly wrap around the campground hose bibb and I place a "bag" made of Reflectix over the heat taped hose bibb and secure closed with a bungie cord. Most campgrounds that are open in the winter have their pipe stands heat taped and insulated. But the bibbs usually aren't protected. On the city water inlet on the side of the Class C, I put one of those foam hose bibb protectors like what you would use on a house hose bibb. I wrap a section of the heat tape around the metal connections and cover it all up with the foam cup (you have to notch out to allow the insulated hose to fit inside the cup). I leave my hose set up like this all year unless I am stripping off the insulation to replace. The foam cup and Reflectix Baggie get put away so that I can loose them and have to redo again every winter.
Best thing to do is to put your water/sewer connections inside a bay to where you can heat them when temps drop to freezing. Means one less thing to worry about, even if you never plan on being in freezing temps.