I finished my basement and added a bathroom (sink + toilet) and a wet bar (sink). I am using a SaniPLUS system. My original plan was to (reluctantly) run an open air vent from the basement, up through the garage to the laundry room above and tie into the vent line running up through the attic to the roof. This would require ripping down drywall in garage walls, ceilings, and in the laundry room. However, while searching online, I came across a video on YouTube from TheSaniFlow Store where he clearly is using the main sewer line in the basement as the wet vent. Jump to 4:25 in this video to see it described very clearly. I was surprised at this interpretation of wet venting but would be perfect for me...

Wet vents are permitted in my jurisdiction as my house (built in 2015) employs them throughout. Can I avoid all of the drywall rip/tear/rebuild and tie the SaniPLUS vent in as a went vent as described in the image below? Vent would be red, waste would be blue -- both wye'd into the main line adjacent to one another. Interestingly, the drain from the 2nd floor laundry is the existing wye shown in this image -- not sure if that helps me in my wet vent strategy as well?

Wet vent strategy?

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    What plumbing code is adopted in your local jurisdiction? And what size is the main line, and the laundry line, for that matter? Is the only thing on the laundry a washing machine, or is there also a sink or anything else?
    – Ecnerwal
    Sep 15, 2020 at 0:15
  • @Ecnerwal, Per my township's website: "..all municipalities in Pennsylvania were required to adopt the state’s Uniform Construction Code (UCC), which is based upon the most current edition of the International Building Codes published by the International Code Council. The Building Code Official administers the 2009 International Construction Code and the Pennsylvania Uniform Construction Code." Regarding the mainline, it is a 3" drain. The laundry line is 2" from the 2nd floor, and has the washer as well as a utility sink connected to it.
    – ph0t0n
    Sep 15, 2020 at 14:39
  • So, probably IPC, I guess, since that's an ICC product.
    – Ecnerwal
    Sep 15, 2020 at 15:00

1 Answer 1


My thought is that the Laundry line (up between the joists) might be what you really want to tap into for a wet vent in this situation, as opposed to dropping into the main line. 4DFUs of drainage in a 2" pipe is what you have (washer plus laundry/utility sink, each 2 DFUs), and is the maximum amount allowed for a wet vent of that size. Buys you a few inches over the main line (and will be effectively a dry vent 99% of the time.)

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