Dishwasher not next to the sink

[Tyman]

Have a question for you guys.

I am doing a remodel and the dishwasher is not going to be next to the sink and going to be about 7' away.

The dishwasher is my farthest run from the main.

Question, what is the best way to plumb this drain in. I fall under UPC code.

Do you run a stack next to the dishwasher in a cabinet?

Also, is there a need to trap it, due to the dishwasher already being trapped?

The closest vent is at the kitchen sink, 2".

I have presented this question to a few local plumbers and get mixed answers. Just want to know how you guys would do it.

Thank you in advance,
Ty

[Bogart]

In Illinois, we can extend the d.w. drain hose and run it thru the cabinets.

[Killertoiletspider]

Our code would call for it to have it's own vented trap, with a two inch vent being more than sufficient.

[Plumbus]

Is it in a bank of cabinets which connect to a sink cabinet? If so, run it through the back of each one until you reach the sink cabinet. If not you can run it in copper below the floor (assuming it's a crawlspace). There's nothing in UPC (any addition) that contradicts the above.

[gear junkie]

Run it to the garbage disposal.

[Killertoiletspider]

Run it to the garbage disposal.

That's a code violation in Illinois.

[Herk]

I'm with Plumbus. Through the floor if it's easier than through the cabinets.

I built my own cabinets, so was able to run through them as part of the design. I have always used 5/8" heater hose, now dishwasher hose that's identical.

[gear junkie]

That's a code violation in Illinois.
Never would've believed it. Any reason why?

[Killertoiletspider]

Never would've believed it. Any reason why?

Hot water should never be used in a garbage disposal, it even tells you that in the owners manual.

[NHMaster3015]

UPC will let you either extend the hose through the cabinets and connect as usual under the kitchen sink. (don't forget the vaccuum breaker) or run it to a trap beneath the floor. (don"t forget the vaccuum breaker)

[JCsPlumbing]

Hot water should never be used in a garbage disposal, it even tells you that in the owners manual.

I think the manuals state to not use hot water while USING the garbage disposal.

J.C.

[NorthernIllinoisPlumber]

Never would've believed it. Any reason why?

Perfect situation for a flood. Too many times, food is put into the disposal, and not ground up. Dishwasher runs, drains...water all over!

[Tyman]

It is on a crawl space so, I think I will trap it below the floor. Just wondering how some of you guys do it.

[gear junkie]

Everyone here runs it to the garbage disposal. I learned something new from you guys. Thanks.

[Plumbus]

Hot water should never be used in a garbage disposal, it even tells you that in the owners manual.

If you can't run it through the disposal, why do they provide a 3/4" waste inlet at the top of disposals?

[Ace Sewer]

If the drain plugs, it is better off run to the disposal; then you have a double sink's worth of storage. When they are run to a separate trap under the sink cabinet is when I see the flood.

And, c'mon, hot water in a disposal makes a problem? It may well say not to do it but if it really hurt anything we'd all be replacing so many disposals there'd be no time to do anything else.

[PLUMBER RICK]

not sure about everyones opinion, but having installed several thousand dishwashers in new construction with commercial plumbing inspectors. the inspectors for the most part only allowed the distance that the factory hose could reach.

in the old days, d.w. didn't come with the hose so they would allow a developed length of 6' to the air gap.

there were times that we did have to drill an air gap into counter top. the discharge line 7/8'' still had to be graded to the disposal.

now in the really old days, the dishwashers typically had their own trap stubbing up into the bottom of the dishwasher compartment.

if it's not going to be inspected, then i would say you can run a line to the air gap. inside the cabinets rubber is fine. under the house use copper.

too much distance will cause standing water in the dishwasher as the pump shuts off, the water will come back to the dishwasher. a simple check valve installed accessible outside the dishwasher compartment will cure this.

if you need to install a separate trap, remember that you still need an air gap with 90% of the machines and an air gap not installed in a sink is a flood waiting to happen. a high loop is not legal here.

rick.

[Herk]

the inspectors for the most part only allowed the distance that the factory hose could reach.


Good grief! What code were they citing for that?

too much distance will cause standing water in the dishwasher as the pump shuts off, the water will come back to the dishwasher.

Water seeks its own level. The only part that can come back is what's in the vertical part of the pipe. What's in the horizontal won't make any difference. The amount of water with the pipe running beneath the floor will be exactly the same as if it were right next to the sink and piped in the cabinet since the level of the bottom of the dishwasher remains the same.

[PLUMBER RICK]

Good grief! What code were they citing for that?

look at section 301.1.1 approvals the manufactures third party certified/ listed research report.


section 807.4 air gaps


section 404.4 wye branch tail pieces.



Water seeks its own level. The only part that can come back is what's in the vertical part of the pipe. What's in the horizontal won't make any difference. The amount of water with the pipe running beneath the floor will be exactly the same as if it were right next to the sink and piped in the cabinet since the level of the bottom of the dishwasher remains the same.

this is true. until you take into affect the laws of physics and siphon-age.


what it boils down to is the what the manufactures approved specs are.

i just got off the phone with the plumbing inspector who answers the phone for code questions. we both agreed that the manufactures specs are the ones to go by. although he did bring out his old school #'s of 30'' horizontal plus the 36'' to air gap.

the specs of each manufacturer will be the deciding factor if in doubt.

sort of the same mentality of a plastic hose bibb on a water heater drain. approved as a unit, not independently.

rick.

[Plumbus]

Anyone remember built into the wall air gaps?

[ridgidpipe]

In Ohio we usually run the lines through the cabinets or the floor whichever is easiest plus we are not required to add the air gap on the discharge line the high loop under the sink is Ok with the inspectors here .

[DuckButter]

Hot water should never be used in a garbage disposal, it even tells you that in the owners manual.
Then you have to wonder why GD's come with a dishwasher tee attachment.