Winterizing with black tank not completely empty

[hampal]

Is it OK to winterize with the black tank not completely empty? When we dumped at the end of our last trip the dump station apparently wasn't level and I don't think we got everything out of the tanks even though nothing was coming out the drain when we finished. When we got home and checked the tank levels we discovered our grey tanks were not completely empty (the black tank always shows full so I don't even bother checking that). I dumped the both greys onto the grass and got a couple gallons each. Based on that I'm guessing there's 3-5 gal in the black tank too but I cant just dump that on the yard. I'm sure the neighbors wouldn't appreciate it. It would be inconvenient to hitch up and tow 10 miles to nearest dump station, and pay whatever they charge, just for a few gallons.

Here's my question. When I winterize can I just leave he black tank as-is and pour some extra antifreeze down the toilet? Its a 45 gallon black tank so there should be plenty of space for expansion.

[TedS]

Sure, put some antifreeze in it. I also put antifreeze in the greys in case they aren't completely empty.

[Cate&Rob]

hampal

Welcome to our owners technical forum. When you have a chance, have a look at our welcome post. https://gdrvowners.com/forum/main-fo...to-new-members . This will help you set up your signature and navigate the forum.

The problem with leaving liquid in a black/grey holding tank is possible freeze damage to the gate valve and if the gate valve leaks (even slowly as many do), this can fill the drain manifold which would likely crack if it froze. It takes a lot of antifreeze to dilute water to where it won't freeze. Not the most "pleasant" solution, but you could drain the black tank into a pail and dump this down a house toilet.

Rob

[Jlawles2]

hampal While not the greatest non smelly solution, a 5 gallon bucket (or whatever fits) under the drain will collect what you dump. Just open and close the valve in short intervals. Take the contents of the bucket to the nearest toilet and deposit it there followed by a flush. Toilet will not over flow as the P-trap is designed such that the level may go up, but will flow excess in to the drain pipe.

Continue until the tank is empty.

[Scott'n'Wendy]

If it were me, I wouldn't be concerned.
I tilt my trailer nose down for the winter, with the way I believe my tanks are plumbed, there would be nothing against the valves and 3-5 gal in a 40 gal tank isn't worth worrying about. Just my qualified opinion as an electrician...lol

But the solution to draining suggested would not be too difficult. I don't think?

[familytruckster4]

I have emptied our black tank at home a few times. The method described above is how I did it. Its not a pretty task and the advice to go slow when opening is crucial. I would also suggest only filling the bucket half full each time. A full bucket is hard to manage
You could just put a gallon of AF in the black tank and deal with it in the spring. I have done it both ways.