IF your heat goes out ... shut off your water and DRAIN your pipes as best you can from their lowest point (open ALL fixtures so that air gets in them to allow water to drain down and flush your toilet so it drains the tank). If you have any RV anti freeze (NOT car anti freeze) treat all plumbing traps too, including your toilet

I have seen 6 figure repair bills for people who forgot to shut off their house's water when they lost heat and also did NOT drain their pipes before they left for a motel/hotel