Just installed new dishwasher. Dishwasher fills, cleans and empties without issue. Hours later found water in bottom of dishwasher. Turns out when I empty say a pitcher of water into the sink, water trickles into the dishwasher from the inlet, not the drain. Faucet is not on when this happens. I cannot understand how this is even occurring. I then turn on dishwasher and cancel it, and it empties no problem from the drain.

  • Hello, and welcome to Home Improvement. Would you add a picture or two of the piping under your sink? And, you should probably take our tour so you'll know how best to participate here. Aug 27, 2019 at 0:53
  • 3
    How do you know the water is "coming from the inlet, not the drain" when you have already established the emptying of a pitcher into the sink as the initiating event? Aug 27, 2019 at 1:33
  • I am saying the inlet because as I pour the pitcher of water in the sink, I can see it start to come out of the inlet which is about 6 or so inches from the bottom of the dishwasher on the left side. (Samsung Waterwall).
    – Judy
    Aug 27, 2019 at 2:04
  • Daniel Griscom: 1drv.ms/u/s!AhZgHoG3VeKshKknWddcJPvcTYYGRw?e=zYVTLt Link to a couple pics. I know the drain doesn't look that high up on cabinet wall, but The drain hose is velcroed to the top back of the dishwasher.
    – Judy
    Aug 27, 2019 at 2:07
  • 1
    Are you sure it's leaking into an inlet and not the drain? Inlet shouldn't be even close to the drain, right?
    – Mołot
    Aug 27, 2019 at 10:39

3 Answers 3


The alternative to an air gap shown in J. Raefield's answer is a "high loop".

Re-read your dishwasher installation instructions. The drain line must be routed so that at some point between the dishwasher outlet and the sink drain connection it is higher than the fill height of the sink.

This is to prevent sink water from entering your dishwasher plumbing, where is evidently finding the fill valve open.

  • I believe the drain height is adequate, but even if back flow was an issue, how is drain water coming in inlet of dishwasher? They don't intersect at all, do they?
    – Judy
    Aug 28, 2019 at 3:38

Does your dishwasher have an "Air Gap" fitting installed? In some places this is a code requirement, but not everywhere, so installers in areas where it is not required will forego it because it costs extra and requires an additional hole in the sink, so installing it often means modifying the sink or even buying a new one (for example if it is cast iron). enter image description here

Without an air gap, siphoning action of the water left in the drain tube can cause water in your sink to get sucked back into the dishwasher.

  • Do not have air gap, but drain hose is attached to the top / posterior of dishwasher before it goes through cabinet to sink drain. I do not notice backup of water from drain area on bottom of dishwasher. It enters through the inlet inside when any liquid is poured in sink. 1drv.ms/u/s!AhZgHoG3VeKshKkodJb-2OnYL8-5mQ
    – Judy
    Aug 28, 2019 at 3:32
  • Can a problem with the case brake on the dishwasher cause water from sink drainage to leak into dishwasher inlet?
    – Judy
    Aug 29, 2019 at 21:05

Turns out Samsung dishwasher has a case break on side of dishwasher where drain water routes through. In case of drain blockage or whatever it is by design that water would then reroute in this case break and reenter dishwasher through inlet on side of dishwasher wall. Though I had a high loop coming off of my piping, it was on a lateral pipe between dual bowl sink. I had to attach DW drain to one of the sink drains, followed by p trap. Water is now "not" backing up and filling entire drain hose that was causing pressure rerouting into dishwasher. Posting in case others have this issue with water coming into inlet area of dishwasher caused by backflow.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.