Thread: WI code for air gaps

Does WI require an above counter air gap be installed, or can I loop and attach to the under side of the counter? I also have a garbage disposer. I am putting in a granite counter and I would like to avoid putting an above the counter air gap. Thanks for any help.

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I am not sure what WI requirements are, you should check with the local plumbing inspector in your town. Having one is not a bad idea though. They do make decorative type air gaps so it will not be so unsightly. In the picture there is a few examples.

From WI plumbing code.

Comm 82.33(9)(d)1.
1. `Residential type.' The indirect waste piping from a residential-type dishwashing machine shall not exceed a developed length of 10 feet. The indirect waste piping from a residential-type dishwashing machine shall be installed in accordance with one of the following methods:

Comm 82.33(9)(d)1.a.
a. Where an air-gap or air-break is located below the countertop, the indirect waste piping from the dishwashing machine shall discharge to a standpipe. The standpipe shall be at least 1 ½ inches in diameter and shall extend at least 15 inches above the trap weir.

Comm 82.33(9)(d)1.b.
b. Where an air-gap or air-break is located above the countertop, the indirect waste piping from the dishwashing machine shall discharge to local waste piping. The local waste piping shall connect to the kitchen sink branch tailpiece above the trap inlet, the standpipe or to the dishwashing machine connection of a food waste grinder. When the local waste piping discharges to a standpipe, the standpipe shall be at least 1 ½ inches in diameter and shall extend at least 15 inches above the trap weir. Where a hose is used for local waste piping, the developed length shall not exceed 18 inches.

Well since WI allows under the counter air gap. You just need to plumb in another trap with at least a 15" stand pipe. Then you can use the air gap pictured below.

Michael,
I'm with you on that one, I would not want to have that clutter on top of my granite either. Michael Larsons post second paragraph is what I see in new construction the most, a separate trap under the counter with a 15" stand pipe and the dishwasher discharging into the top. This accomplishes 3 things really, no clutter on the counter, no occasional over flow, and most importantly the noise is substantially reduced.

Jim Weyenberg
HouseMaster Inc.
Senior Inspector
2006 HouseMaster Inspector of the Year
920-309-3410

Hello
I also live in Wisconsin and I installed a stand pipe under the sink so the "extra" hole in the sink coul dbe used for a soap dispenser, I did not see the soap dispenser that has the vent also...

I ran the dishwasher and the cabinet had a lot of water in it. I ran another cycle with only a few items and watched the entire thing, there is a few drops coming out the top. I used the tail pipe dishwasher connection to have a good place to connect the hose. 20200903_011958787_iOS.pdf20200903_012022905_iOS.pdf.

How can I stop the leaks?
thanks
Mark

Originally Posted by Mark S Williams

... I installed a stand pipe under the sink to allow for a soap dispenser, ...

A standpipe for a soap dispenser?

Every soap dispenser I've seen has been mounted through one of the holes in the sink (metal) or through the countertop (granite, concrete, Corian, ect). I am referring to a hand washing soap dispenser.

The hand washing waste simply goes into the sink. I see a soap dispenser bottle behind the sink.

Are you referring to a soap dispenser for the dishwasher? Those are built into and part of the dishwasher. And how does a soap dispenser in a standpipe dispense soap into the dishwasher?

Do you have a link to what you are referring to? I have not seen anything like a separate soap dispenser for a dishwasher, especially one which goes into a standpipe.

I ran the dishwasher and the cabinet had a lot of water in it. I ran another cycle with only a few items and watched the entire thing, there is a few drops coming out the top.
.
How can I stop the leaks?

The water is coming out the top of the standpipe, run the standpipe up above the countertop above the overflow rim of the sink.

A standpipe at a sink is quite unusual, typically the only standpipe in a house would be for the clothes washer hose to go into.

Every time the sink backs up, water is going to pour out that standpipe long before the water gets very deep in the sink.

Jerry, I opted to use a stand pipe so the extra sink hole could be used for the soap dispenser. They are not connected.

I ran the dishwasher again today and I think the pipe is basically burping. The water is going in and the air is trying to get out. The air is pushing water out too. A lot more water came out this time than the last time when I ran the cycle without soap, so I wonder if the soap changes the surface tension of the water and this is also a contributor.

What is the best way to connect the discharge to the stand pipe to prevent the burping?

Originally Posted by Mark S Williams

What is the best way to connect the discharge to the stand pipe to prevent the burping?

The best way would be to remove the wye, trap, and standpipe, then connect the dishwasher drain to a proper fitting into the sink tailpiece.

There is no air gap above the countertop now, and still won't be.

Most codes require meeting the manufacturer's installation instructions AND the code, if the code REQUIRES an air gap and not just a high loop (which is what most, if not all, manufacturers call for), then you are stuck with an air gap.

If there is no second hole to put the soap dispenser into, and if there is no way to add a second hole, you'll end up with an air gap and no soap dispenser.

What you have now is a disaster waiting to happen, and it's not code compliant if an air gap is required.