In my area, the ptrap arm length (section between waste stack and ptrap) is limited to one foot per 1/4” of the pipe’s inner diameter. (at a 1/4” per foot slope)

I want to move my washer a bit further away from the waste stack than that (8feet overall), and i can’t enlarge the pipes (because the waste stack is common property in my building — what i own is the 2" threaded insert into it, and everything “upstream” from that).

Could i leave my current ptrap in place and extend the standpipe side of the setup instead? Or do a combination of both— i.e move the ptrap, and then “nudge” the standpipe further?

example drain setup

  • 3
    How far do you intend to move the washer from the standpipe? That dimension will give us a better idea of what you are trying to accomplish. Maybe just a longer hose?
    – RMDman
    Commented Mar 3, 2023 at 13:45
  • about 8 feet away.
    – init_js
    Commented Mar 4, 2023 at 10:36
  • leaving the drain in place, and extending the washer drain hose would be going beyond manufacturer recommendations (1.5m max). would the flexible extension have to run waist-high along the wall on a slope to avoid trapping water?
    – init_js
    Commented Mar 4, 2023 at 10:45


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