I am moving my washing machine as a part of finishing my basement. Can I tap into a kitchen drain pipe (draining my sink and dishwasher) for my washing machine drain? How would this be done?

I imagine a 45° pipe fitting would suffice:

45 deg pipe elbow

but, would that cause a smell from the kitchen in my laundry room?

Since you asked, I live in Virginia, USA.

  • To prevent smells from escaping from the drain, you need a p-trap between the opening and the main drain, just as was done under the sink. Whether and how you can fit that and the necessary header pipe into your proposed laundry location depends on the details of your particular house, as would the details of pipe sizes and fittings and where you splice into the existing drain.
    – keshlam
    Commented Aug 14, 2015 at 2:32
  • Jeff - UK, US or somewhere else? It may matter in terms of code requirements.
    – AndyT
    Commented Aug 14, 2015 at 11:07
  • As you're in the US I won't make this a full answer, as different standards may apply to what I'm used to (in the UK). This tee section allows either a washing machine or a dishwasher to be added to an existing 40mm waste pipe. Simples.
    – AndyT
    Commented Aug 14, 2015 at 12:15

1 Answer 1


Probably not a good idea. Clothes washing machines generally discharge a large volume of water at a high rate, the drain apparatus is built with a standpipe (either inside the wall or outside where you can see it) to accommodate the volume. The standpipe holds the water long enough for it to drain without overflowing. Alternatively, a laundry tub/sink is sometimes used. Your local code enforcement authority might even require a standpipe or tub.

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  • So, If I'm reading this correctly, I CAN tap in to the same drain, I just need a stand pipe?
    – Jeff
    Commented Aug 14, 2015 at 11:31
  • Personally, I'm amazed that drainage in the US can't cope with the volume of water from a washing machine without some sort of attenuation. Surely washing machines are little different from dishwashers? Although I have seen stand pipes used in the UK, most modern plumbing is done with dishwasher/washing machine connections like this.
    – AndyT
    Commented Aug 14, 2015 at 12:18
  • @andyt: Standard top-loading washing machines use many times the amount of water a dishwasher uses. Front-loaders might or might not be as much of an issue.
    – keshlam
    Commented Aug 14, 2015 at 13:59
  • @jeff: Standpipe with P-trap should do it unless something else is going on.
    – keshlam
    Commented Aug 14, 2015 at 14:00
  • @keshlam - thanks for the information. Top-loading washing machines are not common in the UK for domestic applications, so coupled with your comment that presumably explains why Jimmy's answer seems so bizarre to me. I'm very glad I checked the OP's location before trying to answer!
    – AndyT
    Commented Aug 14, 2015 at 14:02

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