Feeding washing machine drainhose into kitchen sink plumbing

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by sandman, Feb 25, 2007.

  1. sandman

    sandman New Member

    Messages:
    4
    I'm putting a stacked washer/dryer in the closet in my kitchen, right next to the sink.

    Is there any way to make washing machine plumbing tie in to the kitchen sink plumbing?

    For example, could the washing machine drain into the disposal like the dishwasher? If not, why not?

    Or, could I put a wye in between between my disposal and p-trap, and make a standpipe for the washing machine to feed in there?

    thanks!
  2. Gary Swart

    Gary Swart In the Trades

    Messages:
    7,397
    Location:
    Yakima WA
    I think you're asking for trouble. Today's washers dump their water very rapidly so a 2" drain is required. As kitchen sink is only 1-1/2". A washer requires a standpipe and can not be solidly connected to a drain. The washer drain must be trapped and vented. So, the short answer is, no to all of your ideas.
  3. stand pipe

    you would be wise to cut into the main kitchen drain line

    as far away from the kitchen inlet as possible.....

    if you are on a slab ,

    get into the wall behind the kitchen sink and
    install a wye at the floor if possible.....

    the kitchen will become a wet vent but will work ok.

    perhaps an auto ari vent on the laundry stand pipe would be in order
    or revent that to the main vent...



    the volume of water from the discharge of the

    washing machine can over whelm any fitting you try to

    rig up on the kitchen arm......


    I had a lady once that actually put a bowling ball over her
    garbage disposal --single bowl --- drain when she ran the washing maching...

    because she had it tied in at the kitchen arm and it would fill up the sink. when it discharged...


    the bowling ball fit the hole perfectly and the weight sealed off
    the back pressure.....

    I guess you could do that if you like. .....with about a 10lb bowling ball ...lol
    Last edited: Feb 25, 2007
  4. if it's a front loading washer, it uses a lot less water than the top loading types.
  5. sandman

    sandman New Member

    Messages:
    4
    Yep, thats part of why I'm asking-- the manual does say that a 1-1/2" drain is sufficient!

    I'm not a pro though by any means which is why I was asking, even though I've never heard of anyone doing that. Just wondering since the sink is right there! Having looked it over a while it probably wouldn't be much harder to get to the main.
  6. I have a 1 1/2" drain too, and it was "code" for a top loading washing machine in 1982. Now I have a front loading washing machine. Why Code changed probably has to do with the bigger distances in larger homes. Ultimately the big thing with pipes is their ability to handle carrying water a certain distance and not more, so a 2" diameter pipe is obviously able to carry water a lot longer distance. In your case this whole discussion is irrelevant since the drain is only a few inches away.

    In your second paragraph above I can't figure out what you meant completely.

    I think you are being told by the experts that you need a standpipe. Going through the disposer does not make anyone feel comfortable...

    Ask the manufacturer what people do in Europe. Ask the manufacturer how much water comes out, and compare it to the discharge from a dishwasher.

    After you have that information ("Just the facts") you can ask for some plumber's blessing.

    david
  7. jimbo

    jimbo Plumber

    Messages:
    8,997
    Location:
    San Diego
    I don't know if code allowed 1½" in 1982, but we all know from experience that some places were installed with 1½" and it doesn't work very well. It was marginal in 1982, and worse today due to the GPM of today's WM pumps.

    You must have a standpipe. Connection to a wye under the sink strainer does not qualify. Remember that a washin machine can only fill to the level the drain hose is at. With your hose down low like that, even a front loader would have a problem.


    This is one of those discussions which could go on all night and turn ugly. We have told you that code requires a much different hookup than you propose. If you want to thumb your nose at the plumbing code, it's your house. We cannot give you advice on how to install something "out of code".
  8. sandman

    sandman New Member

    Messages:
    4
    I was just talking about using only one p-trap, the one already there for the sink. But I think I can get to the main and just add in another one.

    That is a smart way to do it! I just checked and the washer puts out 20 gpm. For dishwashers I found on a website that the range is from 6 to 52 gpm. I would guess most household dishwashers are at the lower end of that range.
  9. sandman

    sandman New Member

    Messages:
    4
    I'm not thumbing my nose at anything, just chatting here.

    Surprising that for a moderator yours is the only post thats been "ugly" so far.
  10. Gary Swart

    Gary Swart In the Trades

    Messages:
    7,397
    Location:
    Yakima WA
    It sounds like you are hell bent on doing what you want to do regardless of professional advice and rational, so go just have at it.:mad:
  11. jimbo

    jimbo Plumber

    Messages:
    8,997
    Location:
    San Diego
    Did not intend anything ugly. We often seem here to get into discussions where poster wants to do something and " won't this work OK?" and "this seems OK why does code say no?"...... Those discussions are the ones that usually go awry, that't all I was getting at.
  12. Terry

    Terry Administrator Staff Member

    Messages:
    15,419
    Location:
    Bothell, Washington
    I grew up in a home with a 1.5" washer drain with a fairly short standpipe.

    It flooded so many times, that finally my father took a chainsaw to it and cut out all the dryrot, or maybe it was wet rot, and left a gaping hole to the crawlspace for years.

    When I became a plumber, I tore apart that room, plumbed in a full bath, two lavs, one toilet, one shower and one deep soaking tub, and flipped the washer drain to the garage side, 2" this time.
    With the 2" drain and standpipe, it never flooded again.

    So the morale to this story is, if it floods too many times, you get a nice bathroom out of the deal.

    By the way, my daughter's disposer was backing up so bad the other day, I had to take the 7/8" hose off between the air gap and disposer and use a screwdriver on the inside to clean it out. They had been getting water all over the counter.

    When I've seen existing 1.5" washer drains, I've increased the standpipe size to 2" and made sure they were at least 19" long.
    Last edited: Feb 25, 2007
  13. be nice to newbies.

    i think some people may have read my last post as having come from the original thread question asker. So then they assumed he was "intending", or "hell bent", or whatever.

    Give the guy a break. He has been innocent. We cannot judge his intentions either. I don't think it is wise to discuss anyone's intentions, in any case.

    david
  14. TedL

    TedL New Member

    Messages:
    604
    Location:
    NY Capital District
    Just to drive another nail into the coffin that the initial suggestion belongs in...

    Clothes washers put out clumps of lint, forgotten tissues, etc, that could readily clog up the small drainage holes in a disposal, leading to sink overflow.
  15. coffin buried

    thank you Ted. That seals it and buries it for me.
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