I ran my dishwasher for the first time after a long absence and was unpleasantly surprised by a flood of water out from under my sink. After cleaning up the water, I looked under the sink and I see a suspiciously disconnected flexible pipe which originates from the dishwasher.


You can see this pipe roughly in the center of the photo, it's ribbed and whitish with a very dirty looking metal end. It's physically located very near what appears to be a small aperture on the garbage disposal. It's one of two lines connected to the dishwasher, the other being water, so I'm guessing that this might be the drain pipe.

Is this supposed to be connected to the disposal? (And if it is, is this something I could fix myself? I've never done much plumbing beyond fixing leaky faucets.) There's no other obvious place that looks like it could be connected to.

I can add more photos but the underside of my sink is pretty uninteresting.


4 Answers 4


I think you will have to replace the dishwasher drain hose. The end is so scaled up and worn that I think it will be difficult to install it leak-free. But you may as well try. Replacing it will be a bigger job.

Here is what to try:

enter image description here

You say the end of the hose is metal. It SHOULD be rubber. Hopefully it's rubber, and it has hardened and just feels a bit like metal? The large end, iF it's rubber, should fit snugly over the disposal's unused port. If it really is metal, see if the smaller part of it (the other arrow in my pic) is rubber and fits? And the larger metal one is just slipped on? Then remove it. Either way, or by replacing the hose, you need to clean up the rubber end by scraping it and using a descaler or vinegar. Make it smooth and clean but without cutting slits or cracks into it. This has to make a seal over that port.

Your cleaned up (or brand new) rubber end needs to fit snugly over the small unused port on the disposal. You also need to install a hose clamp on it. Not a spring-clip hose clamp such as on the lower pipe, but a screw-down one, because it's under pressure from the dishwasher's drain pump.

Before you connect the hose to the disposal make sure the unused port was prepared by breaking open the seal. If you stick a pencil or screwdriver in the hole, it should go all the way in so you can see it through the bottom of the sink. The disposal is shipped with that hole sealed up, you have to unseal it by smashing off the plastic disk molded inside it. It's not always easy, and you might need to remove it from the sink and lay it sideways on the floor so you can hit the seal hard without the whole thing bouncing around or damaging your sink.

In the end it should look like this

enter image description here

Finally, read elsewhere about the "high loop" required for the drain hose. Basically, the hose needs to go up high above the disposal then back down to the disposal port. Read about it before doing the job.

If you end up having to replace the hose, look on youtube for tutorials on how to do it with your model of dishwasher. With different brands it can be very easy (a similar rubber socket on the back of the machine) or very hard (disassembling half the machine) or in between. If you're not comfortable with that kind of work get an appliance repair person to do it.


I think there is no o-ring.

The disposal looks very new, so my guess is that someone replaced the disposal. They couldn't figure out how to detach the white dishwasher hose from the light gray stub on the old disposal, so they sawed the whole old stub/hose off and left it hanging.

You need to remove that gray stub from the hose or otherwise figure out how to get an end on there that will fit over the new black disposal stub. It looks to me like the black drain pipe stub is ribbed, not threaded, but it's hard to tell without better photos.

Perhaps a short flexible rubber sleeve that can be clamped over the gray end and the black stub with good worm gear hose clamps?

  • OP says gray end is metal, so I could be wrong about the cutting off. Still think a rubber sleeve with clamps would be a good easy fix.
    – Armand
    Sep 19, 2023 at 22:47

You had water under the sink because the dishwasher drain hose was not attached to the nipple on the garbage disposal as it should have been.

Your pictures tell the story. There is obviously a new disposal. Someone replaced it and disconnected the DW drain hose from the old and did not attach it to the new disposal.

However you cannot just attach the hose to the nipple (red mark). New disposals are shipped with the DW nipple blocked with a "knock out ".

If the knock out was removed you would have water under the sink whenever the water in the sink is run. To be sure the knock out is there, you can probe the inside of the nipple with a screwdriver. If the screw driver stops after just about 2 to 3 inches, the knockout is there and needs to be removed. To do so get a heavy screwdriver or a flat punch and a hammer. Put the punch in the nipple and rap it with the hammer. ( It doesn't take great force.) With the disposal unplugged or the breaker off, (Safety first) you can retrieve the knockout plug from the blade plate of the disposal. Long needle nose pliers, a grabber tool or even a stick with double-sided tape can help.

Then you can attach the hose to the nipple.( there is no O-ring). If the rubber end, ( it is rubber, even if it looks like some metal and may be hard.) is too worn it can be replaced by cutting the plastic hose (see the blue mark in the pic) and replacing the Drain hose connector.. You will need a new clamp if you use the old hose end. a new end comes with the needed clamps.

The last thing to know is the DW drain hose should have a high loop, Higher than the bottom of the sink.

enter image description here


It is pretty clear it is the dishwasher drain pipe.

Why was it disconnected in first place will remain mystery.

Check the o-ring clean it and connect.

It might still work despite the heavy rust, if not you need a new one.

If you have to replace the hose, you need to pull the dishwasher out. Usually they are held by two screws under the counter.

  • I see no o-ring. Do those come in standard sizes? Sep 19, 2023 at 21:53
  • @RoddyoftheFrozenPeas there used to be a o-ring or a rubber seal, that might be lost now. They come in standard sizes.
    – Traveler
    Sep 19, 2023 at 22:02
  • 1
    I believe the gray "end" on the dishwasher hose is rubber or something like it and needs to be attached to the disposal with a hose clamp. It might just be very old and crusty.
    – gnicko
    Sep 19, 2023 at 23:59

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