From the bloggers at RVing.
RV dealerships are only concerned with what damage ice in the water system will do to your RV. When water freezes and turns to ice, it expands. This will cause pipes to split, tanks to rupture, and pumps to fail.
To properly winterize your RV water system you need to drain it, evacuate the remaining water with compressed air, and pump RV antifreeze through the system. RV dealers will perform this service for you, but their labor rates are close to $100 an hour.
To read the full story by RVing, click here.