Considering a pretty drastic change in our ground floor "townhome" but looking at it, it could solve many challenges we have with our place and allow us to not move.

Here is the question: What needs to be considered when trying to connect a kitchen to a condo (shared) bathroom stack (water intake and waste piping)? New items would include: kitchen sink, fridge (water line), dishwasher, (+ optional item: a wall mounted toilet to add a powder room under stairs rigt next to stack as well). Is there ANY possibility to do this or is it impossible/forbidden by code? Local area (IL) is using 2012 International Building Code. I understand the HOA also needs to provide approval but looking to see if it is even allowed in the first place or even possible, and if so, what needs to be considered

Some info about the building: 1985 building. It is an odd layout, with 2-stories "townhouses" units stacked on top of each other (1 bottom unit covering 2 floors, 1 top units covering 2 floors) with an underground garage. Concrete floors/ceiling can make things a bit tricky. Plumbing for the (downstairs) kitchen+washer and (upstairs) bathrooms are on separate shut off (shared by both units). Bathroom stack is shared with upstairs unit and is located in the dining room, exactly where we are looking to move the kitchen. Sink/dishwasher/fridge would be in a row right next to this stackand right below the plumbing wall upstairs. Unit is a ground floor one with the common garage underneath. Water pipes and shut off are also visible and accessible on the garage ceiling right below the unit.

I estimate the current bathroom stack handles: 2 sinks, 1 tub, 2 toilets per unit. No fixtures on the ground floor to that stack currently. Currently getting original blueprints to better understanding.

Adding real shitty drawings per your request. Of the floorplan and the general plumbing stack layout. I don't have all the info yet: not sure where the current kitchen intake/waste pipe comes from, not 100% sure where the 2nd floor washing machine drains (assuming the kitchen waste pipe) enter image description here enter image description here

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    Including a basic sketch showing the layout of the building and current and proposed plumbing would help. You can edit your post, then simply drag the image into the edit box - the site will upload & host for you. The drawing doesn't have to be fancy and to scale, just an understandable MS Paint or envelope drawing with approximate dimensions would be sufficient.
    – FreeMan
    Sep 15, 2021 at 16:07

1 Answer 1


Yes. That's really the only thing I can say is, yes. This can be done and a smart person would have laid out the new kitchen location to do exactly this.

You are attaching to a main stack. There really aren't any major requirements. You may need to get creative about venting, but probably there are options already there.

When you open the walls, the "how" may be harder to answer and your neighbor may not be able to use plumbing for a few hours but this is not rocket science and main stacks get retapped all the time.

  • Thanks @DMoore. That is actually really helpful. Venting is definitely something we are thinking about both plumbing vent and exhaust fans. Currently no ducted exhaust, and looking to see if we can connect to the upstairs duct which is right above new kitchen. I am also planning a 9-12" space behind new kitchen for all plumbing/venting etc.. so that should help with plumbing hopefully. The good news is we can open the bathroom stack now with little issue as it is just a bump out in the dining room.
    – Erik1776
    Sep 15, 2021 at 19:38

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