By "water compartments" I presume you mean the water tanks (black, grey and fresh)....if so, unless your owners manual or dealer tells you they are...presume they are not.
Tanks are usually not a problem...the piping is.
When we stop overnight...and we have, sometimes in 20 degrees, we open the bottom kitchen cabinet doors and the propane heater sends enough heat down there to keep the pipes from freezing up. You DON'T want the expense of replacing these PVC pipes......
When traveling, we keep around 5 gallons (rinsed 1 gallon milk containers) in the bathtub for drinking and flushing (toilet) use.
In other words, camping in cold...with no tank heaters, keep the MH winterized. Find other ways.
2001 Dolphin 5330 F-53 Chassis
Toad # 1 :2007 Chevy HHR/auto (4 down)
Toad # 2 :2011 Ford Ranger 4WD/auto (4 down)