Hey there, havenÂt posted here in a few years as I have been putting off my kitchen work for a while, but itÂs the last room and now I start the planning. I plan to hire out the plumbing, but need to know the extent of the project in case I want to scrap the idea.

I want to move my kitchen sink from one, interior, wall across the room to the other (exterior) wall. The current sink drain is a bad set up.

It drops through an S trap, into a 3 inch line which runs horizontally for 10 feet. It meets a Y where the vent line runs back towards the location of that sink, only a few feet away and parallel , but higher in elevation. This goes out through the wall to an externally run vertical drain pipe that goes up and vents under the soffit. The other end of the Y drops down into large (6"?) septic line and a similarly large vertical wet vent that goes up and through the roof.

My new set up would put the drain 8 feet from the septic main, 4' along the current pipe, then 4' away from the pipe towards another wall.

I suppose this is going to cause a ton of problems. Going up through the wall next the new drain is not possible in this old house. The best thing I can think of is to A.) move my external vertical vent over to the wall next to the new sink and go straight out after the P into that, with a clean out on the outside. Or B.) loop the vent back down and connect it to the old vent line. I am not sure this is proper though.

AAVÂs are not legal in my state MA (I am fairly sure at least). So I donÂt know any other options.

Before I get too into the planning on this I need to resolve how to do this without a huge expense. Any ideas anyone has would be really appreciated.

All of this pluming sits in an unfinished, open basement so it is easy to work in.

Thanks!