I have a basement grinder pump on the lower level of a bi-level home. It was installed after code required leach fields to be shallower than was required when the house was built. The grinder pump was NOT vented, but was installed by a licensed plumber. The pump works fine, however when the washer discharges, the water is forced through the sewer pipe with such force that it forces water up through the toilet, located between the washer and the grinder pump. If I simply remove the cap on the grinder pump where the vent pipe should have been, it works fine. The house is totally finished and I am not sure I can find a route to run a vent pipe through the walls and out the roof (ideal situation) Can I run a vent from this grinder pump up about 6 feet and then through a wall? I am afraid this would fix my toilet problem, but would create an odor problem right outside the front entrance door. Any suggestions? Can I run the vent line into the top of the main sewage discharge line?