Freezing Weather

We are on our third motorhome and I believe in this general rule:

Except for perhaps very extreme cold temps (less than 10- 15 F), if you have enough heat on to be comfortable in the coach, you will not have anything freeze.

This assumes your heating source/s work properly and your RV is designed so that some heat is provided to the 'wet' bay where your water pump and dump valves reside. Now, if you have roof AC's that double as heat pumps, they are designed to heat only the living area and not the wet bay (that is usually provided by a duct from your LP furnace or hydronic heating system (heat exchanger). If you want to provide heat to your plumbing bays, you will need to use your LP furnace of Aqua Hot if applicable.

All this said, 31F is not going to be a problem for one night.

Go read my post in this thread, we survived 14 below and single digit highs for three days.

I've been camping in the low 20s and had no issues.

For one night with the furnace going, you should be good down to 25d anyways unless you have a very stiff wind blowing. We've done a little colder than that without a problem.

Bill

Not at 31

31...you will be fine. If you want to feel good, run the heater, but not necessary.
Have a good trip.