I am considering a kitchen remodel in the next few months and am looking into moving the sink to under the window. It is currently located on an interior wall and the wall I would like to move it to is adjacent to where it currently is and is about 8 feet away. My question is, assuming I could get proper slope for drainage and venting, would it be possible to hook the new drain line up to the old one? I'm trying to avoid running a drain line all the way back to the main drain. The kitchen is over the basement which is finished, but I would be removing the drywall ceiling as needed.

Also, if possible, I was looking for some feedback on PEX for the supply lines. I've read mixed reviews, however it seems like the quickest/easiest install. The rest of the house has copper supply lines. I would like to run these too off the supply lines coming from the old sink location.

Any input is appreciated, thanks for your help!

You need about 2" of drop over 8 ft. for the drain. Are you putting it in an island? Beware of running an S trap through the floor, they are not permitted. For water, PEX is great, but you will need the proper tools to get from Copper to PEX if you use a PEX crimp connection. You could use Shark or Gator bites but they cannot be in a concealed space, walls or ceilings. Venting may or may not be an issue, depending on what you currently have. You may be allowed by local code to use an AAV, you need to check that.

Thanks for your response. I was going to have the S trap under the new sink location, then run into the floor to hook up with the old drain line. It will be going on a wall.

S trap not allowed. P trap required. Consider an AAV at the new sink.

If you run 8' of drain, install Air Admittance Vent under the sink. Check with your Inspector if AAV vent is allowed in your area

SharkBite type fittings are certified to be installed in concealed locations ( walls, ceilings, etc - and also under ground). Check with your local inspector if they are allowed by Plumbing Code governing your area

PEX is replacing copper as pipe of choice. Our Liability Insurance just went up by significant percentage, because we still work with copper.

Combine PEX with SharkBite fittings, and you are done in no time

Hope that helps

Milo

Thanks, appreciate the input. I'll be getting started in a few weeks, I'll let you know how it goes!

Ok so I removed some drywall from the basement ceiling and did some exploring. I was able to find the sink drain, however the drain starts to run over to the stack immediately after it’s through the kitchen subfloor. If I ran the new drain 8ft with a 2in slope I’d end up under the old drain. I’m assuming there’s no way I’d be able to hook up the new pipe to the old at the point since I would have to go back up, correct?

Another option I as looking at was connecting the new drain to my washer tub drain which then runs into the stack under the basement floor. Would this be feasible/permissible? Thanks!

You can either:

1. drill holes through floor joists to build up slope ( you need 2x10 joists minimum to drill for 2" pipe )
2 run drain in the wall, behind kitchen cabinets, then drop it through the floor closer to the main stock

You could connect to washer drain, provided, it is 2" drain. However, we don't like to connect kitchen sink drain to washer drain because kitchen drain is the dirtiest drain in the house, which may make washer to back up

Hope that helps

Milo

Thanks for your response. I’ll take a little more ceiling down in the basement to see how difficult it’ll be to connect directly to the stack. If it’s too much of a pain I may end up just going with the washer tub option. If that’s the case, I’ll run the drain over to besides the tub, drop it straight down and connect with a t joint. This is all easily accessible in the basement so in the event of an issue I’ll be able to get to it.