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whizbang's avatar
whizbang
Explorer II
Oct 04, 2018

Sub-freezing weather and Exposed Tanks.

We are about a week into a three week fishing trip in Montana. We are currently in Missoula.

Night time temperatures are forecast to be in the low 20's all next week.

Our black and gray tanks are completely exposed. There is very little exposed pipe since the valves connect to the tanks with short 4 inch long rubber hoses. Our Winnebago Minnie does not have heat strips on the tanks.

How cold can it get before we have a problem?

Can I dump pink antifreeze in the tanks (diluted) to protect the tanks and valves?

I cold camped years ago in a truck camper and got along with anti freeze down to 19 F. This trip we will be in cold weather for a longer period of time and have a higher volume to waste fluids.

Should we just head home?

14 Replies

  • Windshield washer fluid will do the job and it’s cheaper than the pink stuff. Obviously not to be used in the fresh water tank.
  • At a minimum I would dump some antifreeze into the tanks and disconnect from shore water at night - inexpensive and no downside.
  • Will you be at a campground with a dump station or hookups? If so, you could just dump your holding tanks before going to bed each night that is shaping up to be cold.

    I also suspect you'd be fine without doing anything, but I also won't be around to worry about the mess if that proves to be incorrect. RV antifreeze wouldn't do all that much in the holding tank unless you put a whole lot down. I would suggest rock salt as a better antifreezing agent to use in this case. Even if things froze, though, I don't think it's too likely you'd suffer holding tank damage with your setup. If you have plumbing runs exposed underneath for the fresh water system, they would be a much greater concern for me.
  • You will probably get varying answers, but I think you will be fine as long as your motorhome is kept heated, and the daytime highs are above freezing. I've camped many nights in the 20s with no antifreeze and had no issues as long as the unit was kept warm. Also, the fuller the tanks are the more they will resist freezing.