We've done many week-end winter truck-camper and/or TT trips, in the 60's and 70's, in temperatures well below freezing (often in the minus 20's F); along the north shore of Lake Superior (Soo to Thunder Bay). We often headed out from our Wawa home, one day ahead, just to dig out a 'space' into the snow shoulder of the Trans-Canada highway, and then returned after work on Friday, to use that space for a delightful winter experience, on snowshoe trails, or ice-fishing.
But we would never have considered ANY on-board water uses. Frozen tanks and lines were always avoided. We had no electricity, heated and cooked with propane
, and put #1 and #2 outside, in the bush, like the moose and wolves do.
Such winter camping is a beautiful experience. We have only recently acquired 'Lily-Pad' and expect to relive those earlier adventures again - 'sans agua!'.