The drain line for my kitchen sink currently drops vertically through the subfloor and makes a 90 degree turn in the joist bay below.

Front view of current location

I am relocating the sink, pushing it about 20" back, e.g., perpendicularly away from the horizontal run of the drain. In order to keep the vertical drain in the sink cabinet, I would have to make a 45 degree bend below the sanitary tee and then run at that angle through the cabinet base and into the joist bay, and then tie into the horizontal run from there.

Side view of new location

Would this be allowed by code? Would it lead to clogs?

  • Is your drawing profile view or isometric? I.e., is that 45° with respect to horizontal?
    – isherwood
    Jul 26 at 20:46
  • Yes, it is with respect to horizontal (the angle is not to scale).
    – Brad Stiff
    Jul 26 at 20:47
  • Normally that move would be done under the floor, on the horizontal run. Is that an option?
    – isherwood
    Jul 26 at 21:17
  • Do you mean to install a new horizontal run in the next joist bay over? I don't know what issues I would run into trying to tie the new line into the downstream part, as I can't see it.
    – Brad Stiff
    Jul 26 at 21:29
  • For vents, 45 (or more) is defined as vertical. I don't believe that applies to drains.
    – Ecnerwal
    Jul 27 at 11:39

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