I'm remodeling my kitchen and would like to move my dishwasher about 10 feet farther from the sink than it is now (currently 6 feet of drain hose required). Rather than hook two drain hoses together and routing it behind my cabinets, I noticed something that may simplify things. I noticed that there is a vent pipe going through the roof directly behind where I want to move the dishwasher. Can't I connect the drain hose to the vent pipe or is there a problem with this? If there is no code violation, I was thinking of inserting a 2"X2"X1.5" wye in the vent pipe, putting a 1.5X.75" bushing in the wye, followed by a small piece of .75" pipe jutting out of the wall and attaching the drain to this instead. Will this work or is there a better way? I really don't want all that drain pipe snaking through my lower cabinets. Thanks!

Which plumbing fixtures (from below by your description) are served by this vent? As convenient as it may be, vents from floors below may not act as drains for fixtures above...

Back to you...

Mark

It is a one story house. As far as which fixtures are served, I'm not 100% sure (I'll look in the crawl space today) but it is only close to our kitchen sink (about 10 ft of pipe away).

Determine what the vent is serving so we can be sure we are doing something that won't lead to sewer gasses "burping" into the home, OK?

However, if this vent serves almost any fixture (besides a washing machine) on the same floor level the DW will be on, you can install a 2"x2" x1.5" SANITARY TEE into the vent and then install a PTRAP (absolutely required) with a 20" standpipe. Then you can "indirectly connect" the DW discharge hose into the standpipe and you should be all set here!!

Back to you...

Thanks for the input. I just checked in my (14 inch!) crawl space and the drain pipe appears to serve only the kitchen sink. In the picture below is a drawing (not to scale) of the setup.
So I should put a Tee, not a Wye, huh? There is probably a good reason for that but I don't know what it is. I think your recommendations is what I have on the right side of the drawing right? As for the 20" dimension of the standpipe, is that 20" from the floor? Also, this may be a stupid question but the ptrap and standpipe are all 1.5", right?
Attachment 45370

If this is indeed a vent for the kitchen sink drain then you should be fine connecting into the vent (effectively "wet venting" the kitchen sink drain).

Yes, the Ptrap and the standpipe are 1.5" and yes, a sanitary tee fitting is important because a wye fitting would reduce the effectiveness of the vent on the new DW drain.

Install the Ptrap as close as possible to the floor and then add the 20" standpipe out of the Ptrap...simply stub the DW hose about 12" into the standpipe and secure well.

Back to you...

Great! I already have all of the stuff to do this. I'm not sure how to "stub" the hose into the standpipe though. The dishwasher hose isn't "J" shaped like my washing machine hose and I'm afraid it might work its way out of the pipe. The drain pipe currently has (roughly) a 3/4" female end because it was made to fit on a disposal. What do you think about a device (drawn and attached) that I found at Home Depot that was made to provide an under the sink vent (which I really don't need now) and made to attach to the existing drain hose (a feature I do need)?Attachment 45371

Sorry, either that attachment didn't make it or it is a problem with the site, but I couldn't view the last attachment. I'll try again later.

Sorry, but that attachment will not come up...please try to repost it. Thanks

Attachment 45372


That's weird because it comes up for me on both my computers. I'll try a different format.

Sorry, but here is what I get when I try to pull up either attachment:

"You have attempted to view a Attachment that no longer is available. Please click one of the links in the menu to continue.."

Unfortunately, the site has just updated software and they are having some difficulties, to say the least. We are being asked to weather the storm until the bugs get worked out, so please bear with them.

I'm always checking in and will let you know when I can see the attachment. Until then, and I do hate to say it, but you may have to go to another help site to finish this job if you are in a hurry...*UGH*!!

Happy Holiday!

No problem, It is a simple device. I can just describe it:
Again, since this drain is going behind my dishwasher and out of site, I am thinking I would be more comfortable attaching the drain to a fitting (like on the outside of a disposal). I found a 16"X1.5" drain pipe labeled a "branch tail piece" that will glue directly to the Ptrap. It has a male drain hose connector a few inches from the top. Sitting at the very top is an air vent that only lets air in and not out. Not sure if I need that part and it can be removed and capped if necessary. Thanks for your help on this!

I can't see it either.

Glad to know it isn't just me, Brian (Ma0461).

In terms of your description, Eyjiii, I understand what you are talking about and that will certainly work fine, although sticking the DW discharge hose into the pipe and securing it to the pipe using cable ties would work just fine, too.

Here, if you go the branch tailpiece route, you'll need to eliminate the vent on the male threads, attach a female adapter and raise the pipe to achieve the 20" out of the Ptrap...just cap the pipe after that.

Either way you go, you'll also want to loop the DW discharge hose up high to the bottom of the counter (secure with a plastic clip) before turning back down and attaching the DW discharge hose to the branch tailpiece or pipe....keeps dirty DW water from falling back into the clean dishwasher!!

That should finally do it for you...;)

Thanks! Just curious: What is the significance of the "20 in above the Ptrap" number? Is that some sort of code? Also, is the vent a bad thing? If not, couldn't I leave it on there and still get the 20" by raising the pipe with enough 1.5" PVC right out of the trap and then put the tailpiece in so that the whole assembly is 20" above the trap?

The vent isn't needed...you are tying into a vent, right, so why use the other mechanical vent...simply not needed and isn't how plumbing works...;)

The 20" length is needed to accommodate the water that discharges from the DW...will back up the pipe a bit, so want to have a minimum of an 18" standpipe out of a Ptrap (and yes, it is a code). I would either keep the branch tailpiece low and then extend as mentioned, or just stick a straight piece of pipe up and connect the DW discharge hose using a cable tie.

THanks! I'll try it tomorrow and let you know how it goes!

... can't try it tonight. The vent is ABS and I have PVC fittings and I just found out that there is a special glue for that so I'll get that tomorrow.

That transition cement should not be used in this application. Instead, purchase 2 shielded transition couplings...install sanitary tee with pipe in between (google this) and be sure you won't have any issues down the road (available at all home improvement stores)!

Well I did it! I have watched a load of dishes be washed with no problems (so far so good)! I will repost if I see any problems. Thanks for all your help!

I am glad you are all hooked up and leak free! Thank you for the update!!