Using water below freezing?

It all depends upon what kind of effort you want to put into changing your NOT 4 season coach into a 4 season coach. With exposed (outdoor) pipes, temps below 32 degrees can split those pipes open before morning! However, you can wrap those pipes with heat tape and some foil wrapped insulation and as long as you are plugged in you are good to go. If you have no heat going to your holding tanks you can add heaters in that area in the form of heat mats, tiny portable electric heaters or light bulbs (in you can find non-LED bulbs).
I camp every Winter in VERY cold temps without issue but I have a bus conversion that keeps all pipes and plumbing toasty warm. I just fill my holding tanks and disconnect the water fill line once full. I run off water pumps until it's time to dump and fill again. Never stay connected to a water spigot at that hose will freeze and split overnight.

You can get temperature sensors that have a remote and you can monitor the temps in the area of your water tank. There is also the option of plugging in a personal electric heater (low wattage) that will give off enough heat in the compartment to prevent freezing. The electric heater can be plugged into a thermal coupler that will cut in at a specified temp. My Bay Star gets enough heat in the water bay that I've had no problems when the temps were in the teens if I used the propane furnace.

I'm in Alabama, and I've had my waste gate valves get frozen in our relatively weak winters. No damage, but I could not dump the tanks until they thawed out.

In my old RV the grey and black water tanks are exposed to the elements, and the waste gate valve is hanging out there, too.

Maybe you can stop your tanks from freezing up by dumping some RV antifreeze into your black and grey tanks. Say a gallon in each?

If you just use water from your tank is 1 thing but if you hook to a city water, the hose will freeze upper 20s or less. Also, the valves to drain the tanks will freeze up. If it just get a few degrees below freezing for an hour or 2 might work but colder and longer is a problem.

As long as you have a place to plug in you can certainly prepare your RV to operate into the cold by adding the necessary pipe and tank heaters.

www.ultraheat.com

OP here.

Trailer is an ultralight. No heated tanks. No heated or insulated dump valves.

Sounds like I might be ok, but most likely will have my holding tanks getting slushy. Not sure if it's worth the risk.

As far as winterizing, I would pump in plumbing antifreeze like it is recommended around here.

JaxDad wrote:
A friend found out the hard way, the first part of the grey black tanks is the very exposed pipes / dump valves. Even with an RV with heated tanks these parts are not heated.

Provided it does all work, how are you going to winterize it at the end of the hunt?

Different RVs have differing provisions for heating tanks and such. On my motorhome, the dump valves are in a (nominally) heated compartment along with the tanks, and so protected from freezing.

It gets winterized after use in freezing weather the same as at any other time--drain out the water and sewage, and either blow out the lines or pump in antifreeze. The only difference is that I have to do it fairly expeditiously after I'm done camping, rather than waiting a week for a convenient time.

A friend found out the hard way, the first part of the grey black tanks is the very exposed pipes / dump valves. Even with an RV with heated tanks these parts are not heated.

Provided it does all work, how are you going to winterize it at the end of the hunt?

Wow Sudbury in December? I wouldn't advise it unless you have a MH and all your water lines and tanks are enclosed in a heated basement. Forecast right now for end of November is 15F or -9C. That'll definately freeze any exposed water lines....

In a holding tank, there's usually more than enough room for expansion as the fluids freeze. Pink is relatively cheap -- dump a couple gallons in the tank, and you might be OK.