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Dishwasher drain hose - where would you put it?

Posted by cberhomengarden (My Page) on
Mon, Jun 28, 10 at 22:18

Cross post with Kitchen forum...
We are redoing our kitchen and have an L-shaped design. It is a small space, so to include the dishwasher, it is not right next to the sink, but on the other side of the L. The sink is centered on the long side of the L, then to the left there's a 9 inch spice pullout, a 36 inch super susan, then on the small side of the L is a 18 inch cabinet, and then the dishwasher. Neighbors (whose house is identical, and whose kitchen design I copied) had water intake snaked from sink to the dishwasher behind the cabinets. They then drained the dishwasher down through the floor to drain pipes in a bathroom below in the basement.

Our contractor feels it's better to snake the dishwasher drain all the way back around the L to the sink drain. This would mean drilling holes through every cabinet along the way, and an 8 foot dishwasher drain hose. When I mentioned how it was handled next door, the contractor disagreed.

What are your opinions? Where would you drain the dishwasher, through the floor to a basement bathroom drain pipe, or snaked around the cabinets back to the kitchen sink?
I hope my description of the issue was clear. Let me know if you need more info.
Thanks in advance for any ideas and advice!

Follow-Up Postings:

RE: Dishwasher drain hose - where would you put it?

The answer is simple. Code requires that the dishwasher drain line must begin and end in the same room. It may not pass through a wall or floor.

RE: Dishwasher drain hose - where would you put it?

automotive radiator hose is long and smooth.

drilling holes is easy.
but is unnecessary.

you can send the hose under the cabinets.
it starts out at floor level when it leaves the DW.
from there you don't need to send it high.

high loop it at the sink cabinet or the one before it.

go to ,
where real life practical people will confirm all this.
among them are Master Plumbers with decades of experience.

they will tell you more
the advantages of a smooth hose.
the problems that arise when a drain goes down one floor.

Code is there for a reason.
the problems they will describe are not guaranteed to happen; they are maybe going to happen.


RE: Dishwasher drain hose - where would you put it?

Thank you very much for your replies.
I will have them drain it to the kitchen sink and try to avoid drilling lots of holes in the cabinets.

RE: Dishwasher drain hose - where would you put it?


Going behind the cabinets is the correct way to go. The holes being drilled will be next to the wall & should only be thru each end partition on each cabinet. You will never see them and they do no harm in being there. Running the hose low will trap water in the line which may stink if not used regularly. Running the hose high and sloping to the drain tailpiece will keep the line drained as much as possible.

Take Care,


RE: Dishwasher drain hose - where would you put it?

yes to the way it's described above.
however, for newbies:
it is good to describe the water that remains in the hose after each drain cycle as Not trapped in any way. The hose starts its life at a low-down drain point. Deciding at what point in the line it will go high (and far higher than its connection point to the sink drain) is the question. There will always be water left in the hose, at all times. This is desirable, normal, and necessary. You cannot have a DW hose empty of water. Standing water is always there.

It's also good to spell out clearly for newbies that no DW hose needs to be "drained as much as possible".

It's also good to spell out clearly for newbies not to fear "water in the line which may stink if not used regularly" --- and besides, all DW hoses have water in them at all times. So I tend to think there may not be much knowledge behind that post. The word "tailpiece" is another clue: it's the wrong term, as the tailpiece is the first piece of horizontal pipe downstream of the P trap (part of the P trap), and that is absolutely not where the DW connection is made. DWs are connected above the P trap. Hope this helps.

Fear not.
Whether your hose goes high early in the line, halfway, or at the end.
Eight feet length of hose is a medium long hose.
Ten and twelve feet length have been seen before. That is long.

Call the DW manufacturer if you want their advice about this question.
"How long can the hose be before it goes high?"
"Is it better to loop high at the end or right away at the DW?"
Different DW manufacturers give different answers.

There may ultimately be determined in this forum a "correct way to go" but I wouldn't wait for any group consensus or decision on anything called correctness. In any case, as mentioned above, holes are easy to cut, will not be seen and will not interfere with anything. There is space for the hose. It does no harm being there. You can choose the route it shall take.


RE: Dishwasher drain hose - where would you put it?


For someone to throw around the term "Newbie" soo much, you think you would know a thing or two. In the first paragraph you state "water...not trapped in anyway" and in the paragraph state "Standing water is always there". Thank you for confirming my point.

You talked about using "Automotive Radiator hose" which is much larger than the heater hose I think you were thinking about. Your experienced plumbers would have to use a lot of duct tape to make that one work. And yes it's duct not "duck" tape.

To fill you in, the tailpiece is located between the basket strainer and the p-trap which would be upstream, not downstream from the p-trap. Anyone who knows anything about plumbing knows the dishwasher fitting slides onto the tailpiece (or threaded to the basket strainer) and is exactly where code requires you drain the dishwasher.If you are connecting the DW drain downstream from the P-trap, thats an untrapped fixture.

And thank you for soliciting your WEBSITE and not answering cyberhomegardeners question. If you want to expand your website you can google "plumbing 101" for a start.

Thanks for the laugh!



RE: Dishwasher drain hose - where would you put it?

I'm not aware of
" soliciting your WEBSITE and not answering cyberhomegardeners question."
Perhaps some other person should be the intended recipient.

RE: Dishwasher drain hose - where would you put it?

Under a sink, there are two tailpieces.
1. sink tailpiece: pipe coming out of the sink drain
2. P-trap tailpiece: pipe coming out of the P trap

About trapping water:
There is always standing water in the hose so it's the opposite of a problem.

To say: "running the hose low will trap water in the line" implies it's a problem.
To say: "which may stink" implies it's a problem AGain!
To say: "keep the line drained as much as possible" implies the drain should be drained, and that is not the case.

One could say: "to maintain a smaller amount of standing water" to describe the real situation you were suggesting. Which is a fine situation.

RE: Dishwasher drain hose - where would you put it?

The hose is NOT intended to be a trap.
Standing water is NOT needed or wanted.

DWs drain through an 'indirect waste' into a trap for protection.

The small amount of water in a trap that is used regularly rarely becomes an odor issue.

It is more likely the trap will dry out and allow sewer gas into the house and THAT crates an odor issue.

The waste water from the DW contains food and other organic matter, and if the hose is long and pitched incorrectly can easily develop odor issues.

The DW itself can start to smell if water runs back into it from a long or incorrectly pitched hose.

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