Richard, I can't imagine anyone on the planet wanting to look at yer butt. The lady that came for the inspection in likely went to HR and said I quit!
One thing great about the way our house is laid out, none of the plumbing is on an outside wall. The closest thing to a point of possible freezing is the bathroom in my garage. It is part of the HIVAC system and it is a little room. It stays nice and toasty in there, and the sink side has the garage behind it and toilet has the water connection coming up from the floor. In the 20 years we have lived here we have never had any freezing issues.
It is down to 40 degrees in the garage right now. I have a heater out there, but no reason to run it. 40 is way above freezing point so no big deal.