I have an existing drain set up like this:

Existing Plumbing

I am replacing the existing washer / dryer, and would like to set up the washing machine to drain into a proper laundry box (instead of draining into the laundry sink). The box would ideally be around 6 feet from the existing laundry sink.

Looking at the existing plumbing, it appears to me that the section of pipe between the upper floor and the laundry sink is set up as a wet vent (which, to my understanding, is not to code).

Ideally, I would tap off the vent line 6"+ above the kitchen sink, and then run that clean vent line down to the basement, and branch off for the sink and the laundry box. Unfortunately, the vent line is on an exterior wall, and the other side of it is behind the tile backsplash in my kitchen.

  1. Is the existing setup not to code (because of the wet vent)?
  2. Is there any way I can salvage the situation to preserve proper venting (without tapping into the drain line above the kitchen sink?

For reference, I am in the US (Illinois).

  • I had to install new drain plumbing for my sink and dish washer. I didn't know the codes, but I managed to find an electronic version of the codes and contact information for my city's building code inspection department on my city's web site. It may be worth contacting them with this question, especially since you created such a clear drawing. You will probably have to get a permit to make changes. I hope you can find what you need!
    – John
    Commented Nov 24, 2016 at 12:09


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