I was thinking of putting a check valve on the drain line coming out of the softener. That way if it ever builds up, water won't make it to the softner. It's a 3/8" flexible pipe, and it's being run 30'. The cleanout pipe already has a backflow escape, and if it does, I don't think it will go 30' and up about 3-4' higher than the cleanout pipe.
Ghostmaker, This is a water softener. I can't drain the waste water on water pan, as it will kill any living plant or organism.