Maximum distance for horizontal bathroom DWV?

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by benze, Jul 23, 2012.

  1. benze

    benze New Member

    Messages:
    63
    Location:
    Montreal, Canada
    Hi,

    This may be code/region dependent, but I was wondering if there was a maximum length/distance (logically or otherwise) for a bathroom DWV line. I'm looking to add a half storey to the house, and where I want to locate my new master bathroom would cause some semi-significant demo work in a fairly new kitchen underneath to put in a DWV in the wall. On the other hand, I have a fairly innocuous area that I can run it at the front of the house, but it would have a 40-50 foot run from the bathroom to the stack in the front of the house. Given a 1/4"/foot slope, I figure I would need nearly a foot of drop from the bathroom to the vertical stack.

    Is a 50 foot run considered bad practice if the slope is maintained throughout? Is there a minimum size that I have to run given the distance? If I need 45 to make a couple of bends, is that an issue? From what I understand, minimum size for bathroom drain in 3"; would I need to go 4"?

    Thanks!

    Eric
  2. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,319
    Location:
    New England
    There is a requirement on the maximum number of degrees the pipe can turn before you need a cleanout, but distance should not be a problem if the slope is maintained. Think about the drain line after it typically exits the house...it could be hundreds of feet before it meets up with the area's sewer line - distance isn't the issue, it's the slope - no flat spots, no bellies, a consistant drop of at least 1/4" per foot (2%).
  3. benze

    benze New Member

    Messages:
    63
    Location:
    Montreal, Canada
    That was pretty much my thought process and expectation as well. I had not considered the issue with the cleanout however.

    Does anyone know the requirements for max turns before a cleanout? (I realize that this will likely be governed by code, but just looking for a rough idea).

    Thanks,

    Eric
  4. Terry

    Terry Administrator Staff Member

    Messages:
    15,416
    Location:
    Bothell, Washington
    You can go 135 degrees between cleanouts.
    That's a 90 and a 45
  5. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    27,258
    Location:
    Cave Creek, Arizona
    Here it is 90 degrees, but 135 degrees for a trap arm.
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