I know there is a lot of info here about winterizing. However, i have a specific question I can't find answer to. I just winterized my TT. We still had about 4-5 gallons of water in the black water tank (as you all know, to keep it from going dry and having things harden). Since our last trip of the season won't pan out, I just put 1 gallon of RV antifreeze in the BW tank. (besides all the regular winterizing activities..so this question is about the BW tank only). Will this suffice in the BW tank or should it be empty for winter, or ???Appreciate the info...shouldn't be hard question but it's stumping me right now.

IMO diluting the antifreeze five to one with the water already in the tank would make the freeze protection ineffective. Can't prove that as I always give the black tank a good flush after the last trip until clear water with only a few flakes of TP comes out, then drain it as much as possible. No worries about freeze damage is there is only a little water left in the bottom of the tank.

Get a five gallon bucket and drain it just put a cloths pin on you nose. :E

As stated above a diluted mixture won't give much in the way of protection. I always completely drain mine then add a gallon of AF split 1/3 - 2/3 between black & grey tanks.

For your black tank. Remember water expands when it freezes. So ask yourself. Will 5 gal in a 40 gal tank expand enough to fill over fill the tank with ice? Answer. NO. so flush is as normal, and leave the 5 gal in it to prevent the dreaded black tank dry syndrome. And don't worry any more about it. I have always left 5 gal in the black tank. No problems. There is plenty of room for expansion.

Terryallan wrote:Remember water expands when it freezes. So ask yourself. Will 5 gal in a 40 gal tank expand enough to fill over fill the tank with water? Answer. NO. The tank's not the issue, it's large and flexible. The 4" rigid drain pipe at the bottom of the tank and the drain valve however will burst with only a quart of water in there.

RV antifreeze in BW tank | Good Sam Community

28 Replies

Bumpyroad
Explorer
Oct 05, 2014
JaxDad wrote:
As stated above a diluted mixture won't give much in the way of protection.

I always completely drain mine then add a gallon of AF split 1/3 - 2/3 between black & grey tanks.

in another thread I posted my results where I diluted some antifreeze with 1/3 water and it just slushed up as it was supposed to do.
bumpy
RAS43
Explorer III
Oct 05, 2014
stickdog wrote:
Get a five gallon bucket and drain it just put a cloths pin on you nose. :E

X2 Not pleasant but resolves the issue.
poncho62
Explorer
Oct 05, 2014
Drain it out....I do it after I put the pink stuff in, even though the tank is empty...Better safe than sorry
JaxDad
Explorer III
Oct 05, 2014
Terryallan wrote:
Remember water expands when it freezes. So ask yourself. Will 5 gal in a 40 gal tank expand enough to fill over fill the tank with water? Answer. NO.

The tank's not the issue, it's large and flexible.

The 4" rigid drain pipe at the bottom of the tank and the drain valve however will burst with only a quart of water in there.
Terryallan
Explorer II
Oct 05, 2014
For your black tank. Remember water expands when it freezes. So ask yourself. Will 5 gal in a 40 gal tank expand enough to fill over fill the tank with ice? Answer. NO. so flush is as normal, and leave the 5 gal in it to prevent the dreaded black tank dry syndrome. And don't worry any more about it. I have always left 5 gal in the black tank. No problems. There is plenty of room for expansion.
JaxDad
Explorer III
Oct 05, 2014
As stated above a diluted mixture won't give much in the way of protection.

I always completely drain mine then add a gallon of AF split 1/3 - 2/3 between black & grey tanks.
stickdog
Explorer
Oct 05, 2014
Get a five gallon bucket and drain it just put a cloths pin on you nose. :E
CloudDriver
Explorer
Oct 05, 2014
IMO diluting the antifreeze five to one with the water already in the tank would make the freeze protection ineffective. Can't prove that as I always give the black tank a good flush after the last trip until clear water with only a few flakes of TP comes out, then drain it as much as possible. No worries about freeze damage is there is only a little water left in the bottom of the tank.

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RV antifreeze in BW tank

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