I had a water softener installed a few years back in my garage. I originally wanted it in the back of my garage so it wouldn't get in the way of parking my car. But at that time the plumber said it would be easier to place it in the front ( right by the garage door) since the most accesible drain is a bathroom which was located on the other side of the wall. He installed it with the drain pipe being a simple plastic tubing that went from the water softner in a downward direction into the wall and then into the drain pipe of the sink in the bathroom.
I would like to move it to the back of my garage. To do this I would have to run copper pipes up and over a door way and then connect to my water line. My question is the drain pipe. After searching the internet it said the drain pipe has to be in a down ward direction other wise it can back up into the water softener, yet another post said it is under pressure and can run up a wall as much as 8 feet. My other choice is to run it into my garage drain which I understand is illegal since it drains into the gutter.
I also have a choice of running it along the floor and then into the wall where my sink is which would then be only about a 2 feet rise. There is a small step where the door is so I would have to snake it around the step.
One other question is the sewer gas. The previous plumber simply ran the drain tube into the sink pipe without any provisions for preventing any back flow so I assume it isn't necessary. Any help anyone can give will be much appreciated.