How high can a washing machine pump water "uphill"?

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by JMingrone, Jun 7, 2013.

  1. JMingrone

    JMingrone New Member

    Messages:
    49
    Location:
    Connecticut
    I want to install a washing machine in the basement of a house I just bought. We have a septic system where the cleanout for the sewer pipe enters horizontally through the foundation 54 inches off the slab floor. Any drain I install would have to tap into vertical section of the the main drain pipe at least 64" off the floor. Is there a spec for how high up a washing machine can pump " uphill". Are all machines pretty much the same?

    Thanks,

    Jay
  2. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,324
    Location:
    New England
    Most WM can handle that height, but to be sure, most have that info in their installation/user manual, or if not, a call to their technical support should resolve it. You may need a longer discharge hose than what comes with the new WM...there's a limit on that as well, but the pumps are usually pretty robust. Higher usually isn't an issue (within reason), lower usually is as the tub can siphon dry. You may have a problem getting the stand pipe tall enough starting out that high, though.
  3. JMingrone

    JMingrone New Member

    Messages:
    49
    Location:
    Connecticut
    Thanks Jim. I easily have 83 inches to the bottom of the joists, more if I go up inside to the subfloor. The standpipe sounds like a length of vertical pipe above...what, a trap? How tall does it have to be?

    Good idea on checking the WM manual.

    -Jay
  4. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    27,263
    Location:
    Cave Creek, Arizona
    drain

    It does not "have to b"e any specific length, but regardless of what its height is, if the septic backs up the water will overflow the standpipe and flood the basement. And you do not want to prevent that by fastening the drain hose to the trap, because then the back flow will fill the washing machine with sewage.
  5. JMingrone

    JMingrone New Member

    Messages:
    49
    Location:
    Connecticut
    So assuming that's a problem, or could be, what other options are there for plumbing a basement WM?
  6. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,324
    Location:
    New England
    Code wants the standpipe to be 2" with a trap (all traps should be vented) and within a range in height. This helps to manage sudsing, splashing, and keep everything flowing well without overflowing. Don't remember the number right now, but it shows up if you search a bit.
  7. cacher_chick

    cacher_chick Test, Don't Guess!

    Messages:
    3,281
    Location:
    Land of Cheese
    The washer should be discharged into a code approved standpipe which discharges into a sealed basin with a pump in it.

    This could be done with something like a Liberty 405 or if you foresee the possibility of any additional fixtures in the future, a common sewage basin and pump system can installed below the floor. Either of these systems would prevent a sewage backup into the basement or washer.

    The plumbing codes in most areas are quite clear as to the allowed height of a washer standpipe.
  8. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,324
    Location:
    New England
    If you can make the standpipe at least 18" high (it must be less than 42"), it should work. Since that connection is likely the lowest one in the house, there's always the risk of it backing up if there's a clog downstream of the washer's discharge. A checkvalve may provide too much flow restriction and cause the standpipe to back up and overflow which is where a separate pump with a storage basin has advantages.
  9. JMingrone

    JMingrone New Member

    Messages:
    49
    Location:
    Connecticut
    Thanks everyone for all the input, I think I have enough to go on!
  10. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    27,263
    Location:
    Cave Creek, Arizona
    washer

    quote; should be discharged into a code approved standpipe which discharges into a sealed basin with a pump in it. I have never installed a sump pump in a "sealed basin", but have installed MANY ejectors into sealed basins. A washing machine ONLY needs a sump pump.
  11. LLigetfa

    LLigetfa DIYer, not in the trades

    Messages:
    4,185
    Location:
    NW Ontario, Canada
    I'm guessing that code varies by region but in some jurisdictions, grey water can bypass the septic system and be pumped to flower beds etc... might be an option. Some sort of lint trap should probably be used with any kind of secondary "sump pump" type system.
  12. LLigetfa

    LLigetfa DIYer, not in the trades

    Messages:
    4,185
    Location:
    NW Ontario, Canada
    The longer, larger, taller the discharge hose, the more waste water will remain in said hose and likely run back into the WM, creating a possible odor issue.
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