We camped for two weeks every Christmas and a few winter dogs shows. Never had a problem with freezing anything as long as the heat was on, etc.. The only time in our RV-ing history that we had an issue was when we towed the little Prowler TT down to Myrtle Beach and it was going to be 15 degrees that night. It was a Sunday and the line from the LP tank was clogged so, we didn't have any heat (too stupid to run to Walmart for an electric heater). Everything froze solid and when it thawed water started spewing out of the water system drain. I ran to Lowes, bought the parts and fixed it (also replaced that supply line). In 30 years of RVing that's the only freeze issues we ever had. In the motorhome we camped when it was in the mid 20s many times.