OK... I want to move my washer away from my waterwall (currently in the kitchen) into my garage for space reasons and overall common sense. My house is on a concrete slab. The garage is the only viable option. I can sweat the copper from the supply through the walls to the garage with no issues. Once I move the washer and the supply to the garage, what are my options for drainage? There is a cast iron drain about 25 feet away and accessible if I dug the entire 25 feet about 4 feet down... which I would like to avoid. There is a vent cap that pokes through the ground line that leads to the iron drain pipe. Is there some other system aside from digging and attaching washer drain directly to the iron drain pipe? Possibly a type of pump going back through the walls to the water wall? Please help...

Rather then jackhammering the slab and running a vent up consider installing a Sanivite Gray water Laundry Pump, (see image) check them out at;
The perfect, quiet, pump solution to install a complete kitchen or laundry at ground level or in the basement. Let me know what you think. Good luck, Tom,