I plan to be adding 2 bathrooms side by side. Is it possible to do 1 wetwall with all the plubming in it? I attached an overly simplified image as an example.

A few questions.

  1. Is this possible?
  2. This may not be answerable but would this be problematic in terms of being up to code?
  3. Are there any issues that with doing it this way?
  4. I know it may be very hard to access plumbing at a later date if something went wrong since there would be no access panel (or access wall). Is access really need in the future?
  5. What size should the wetwall be in this case?
  6. If this is bad, are there any alternatives or would it just be best to use different walls for each?



Sure, it's done all the time. Thickness of the wall will likely be determined by the required vent size. With two toilets, two tubs and four sinks, I think you'll likely have to go to a 2x6 wall if you go with a single vent stack, but you'd have to run the numbers.

I did run into a code issue with drains T'ing into the main vertical stack at the same level. Still not sure what the issue was, but the made me change it.

As far as accessing it later. If everything is properly pressure tested before you close it in, you should be fine. But stuff happens. The odds of it happening are inversely proportional to how easy it is to access the area. So if you had an access panel there, it would never leak there anyway. Mostly joking, but seriously - if you have a problem, you may have to break into the wall. No fun, but unlikely and not the end of the world.

  • 3
    +1 Plumbing "access panel" is very often "well, you know how to repair drywall (or tile) don't you?" Though you COULD put in a cleanout with decorative cap, or tucked in the back of a vanity, just to improve your odds a little. – Ecnerwal Feb 23 '15 at 23:17

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