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Dishwasher drain vent

CTurk's picture

Is it critical where the drain hose routes through the adjacent cabinet to the vent?  Does it matter if it's high or low.  I'm getting water shooting out of the vent hole.

I have the Y under the vent with the small male end going to the dishwasher drain pipe and the larger one going to the port on the side of the disposal.

I ran the hoses through the cabinet up high to acommadate more storage underneath.

Any ideas what I did wrong?  Thanks for any thoughts.

(post #65045, reply #1 of 9)

Loop the DW drain high just under the counter and drain into the sink's tail pipe.

Check your local codes, most do not require air gap.

Although I don't have first hand experience, I was told not to drain DW into garburator because the detergent could corrode the metal.

Hope this helps.

(post #65045, reply #2 of 9)

Thanks for the reply.  The hole I drilled is not right under the counter but maybe 6-8" down.  I wonder if that makes a difference.

The air gap, I was told by contractor/ handy types, that the gap would eliminate the dishwasher water from burbling up through the sink drain,

The other problem is the single tub sink has no lip to keep the water that comes out of the vent from falling behind the sink on the laminate counter top .

Maybe I should just eliminate the gap, but the reason I put it there was to keep the sink from filling up with dishwasher debris.  Lettuce chunks and such.

(post #65045, reply #3 of 9)

If it would gurgle up into the sink without the gap then it's going to gurgle out of the gap with the gap.

Of all the preposterous assumptions of humanity over humanity, nothing exceeds most of the criticisms made on the habits of the poor by the well-housed, well-warmed, and well-fed.  --Herman Melville

(post #65045, reply #4 of 9)

I don't think I understand. I have hook-up more dishwashers than I can recall and I have NEVER hooked a dishwasher to a ventline or that had a ventline. And where does the Y you refer to come from?

Basically the drain HOSE that comes from the dishwasher goes through the cabinet sidewall as high - close to the underside of the countertop - as you can get it. It then connects to the 3/4" or 1" x 3" nipple that extends out from the disposal unit high up. Be sure to knock out the metal punch-out inside that nipple. It is there in case you do not install ####dishwasher.

Voila! You're done!


Flay your Suffolk bought-this-morning sole with organic hand-cracked pepper and blasted salt. Thrill each side for four minutes at torchmark haut. Interrogate a lemon. Embarrass any tough roots from the samphire. Then bamboozle till it's al dente with that certain je ne sais quoi.

Arabella Weir as Minty Marchmont - Posh Nosh

(post #65045, reply #5 of 9)

I guess I'll try it w/o the vent and see what happens.  Why do they sell vents then?

Is having the hole 6'' below the counter top going to make a difference or should I drill again right below the counter top?  Thanks for the help.

(post #65045, reply #6 of 9)

I thought the vent was to prevent waste water from being syphoned back into the dishwasher from the drain.

I run the drain up as high as I can and leave the vent off.

I've only done two dishwashers, but I've heard no complaints...and both customers continue to call me for other stuff, so I think they would mention a problem.

Rich Beckman

Another day, another tool.

(post #65045, reply #7 of 9)

I had the same problem a few days ago - dishwasher draining and shooting out the air gap vent. Turns out I forgot to remove the disposer knockout where the hose attaches coming from the air gap. Works fine now. I don't think the height of the dishwasher drain hose makes any difference- the drain water is pumped out of the dishwasher, not gravity drained.

(post #65045, reply #8 of 9)

I don't think the height of the dishwasher drain hose makes any difference

With an air gap, it shouldn't make any difference. It would make a difference with no gap though IMHO.

(post #65045, reply #9 of 9)

Thanks for the reples again.  I found out last night from my wife, who is a local property manager for a small development company, that the vent is required by code in our area of the N.W.