My house has a strange bit of plumbing. It's a house flipped by a contractor. It's plumbed for soft water, but there's no sewer near the closet where the plumbing is, and soft water units need a drain to flush water down during their regeneration cycle. The person who flipped this house solved this problem by installing the drain line (1/2" copper) upward to the roof, where there is then a pipe across the roof to a sewer vent.
We recently had a problem where the 1/2" vinyl pipe that connects to the drain pipe came loose. We think it was due to icing in the pipes across the roof, causing the joints to face the full house water pressure rather than just a small amount of pressure like one would expect on a drain.
We are already looking at ways to secure the junction more securely, but I was curious about trying to solve the icing problem. Besides the obvious insulation on the pipes, the next obvious solution would be to drain the pipe.
I can't drain the soft water out to the nearby ground because we have a tree out there, but is there a good way to perhaps drain the standing water out of the pipe?
(or, if I'm totally missing the obvious solution, I'm open to answers which provide a more correct way of plumbing things that doesn't involve hacking up my slab to put new sewer lines in or poisoning my tree with salt)