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?

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.

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.

At a minimum I would dump some antifreeze into the tanks and disconnect from shore water at night - inexpensive and no downside.

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.

We deal with below freezing temps from time to time in Alberta :)If the valves are close coupled to the tanks they will not freeze. If you keep substantial volume of fluid in the tanks they will not freeze if daytime temps go above freezing. You are also adding warm grey water from washing and cooking. They take a long time to freeze unless daytime highs are not going above freezing. Keep a milk jug 3/4 full of water on the picnic table if you are dry camping. The state of the water in it will tell you what is happening in your holding tanks.

Sub-freezing weather and Exposed Tanks. | Good Sam Community

14 Replies

ljr
Nomad
Oct 04, 2018
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.
ksg5000
Explorer
Oct 04, 2018
At a minimum I would dump some antifreeze into the tanks and disconnect from shore water at night - inexpensive and no downside.
DrewE
Explorer II
Oct 04, 2018
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.
rjstractor
Nomad
Oct 04, 2018
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.

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Sub-freezing weather and Exposed Tanks.

14 Replies

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