Dishwasher Air Gap Required

Bobber · Nov 5, 2011

My DW has never had an air gap inline, nor have I had any problems.
Just a high loop and outlet into the disposal.

I just remodeled our kitchen and do not have a hole cut in the stone for an air gap.

My DW installation manual states that as long as the disposal drain inlet is greater than 24" above the subfloor, a high loop with connection to the disposal is sufficient.

My question is can I use the installation instructions as an argument to pass a final inspection?

Jadnashua · Nov 5, 2011

No...an air gap is the only, guaranteed safe way to hook it up. If your local codes require it, that's what you need. Now, there are millions of DW that only use a high loop, but under certain conditions, it is possible to get sewage into your DW with one. That's nearly impossible, requiring multiple faults to happen with an air gap.

Sponsor · 2022-01-29T12:20:58-0800

Gary Swart · Nov 5, 2011

Jim's answer is correct, but some places require the air gap, some don't. The air gap is always legal everywhere, so that is the surest way to go.

Themp · Nov 6, 2011

DW manual

Just did a dishwasher where the manual stated the same as yours and it also stated that a backflow value was also in the discharge line. So, I went with the high loop as I felt this was reasonable and I know not fool proof.

Jadnashua · Nov 6, 2011

IF your local codes require an air gap, you must install an air gap. It's not a bad idea anywhere, but some places, you just don't have a choice.

Tom Sawyer · Nov 6, 2011

Maine requires an air gap regardless of what the manufacturers directions say so.......ask your inspector but, even if he fails it, it's a pretty easy thing to add if you have to. Personally, I hate the damn ugly things.

Terry · Nov 7, 2011

In Washington State I've been required to use either the Air Gap fitting or the Johnson Tee; which works as an air gap, but can be installed in the wall.

hj · Nov 8, 2011

Did the Johnson Tee finally get IAPMO cerification? You CANNOT argue with the inspector and win. If he wants an air gap, you WILL install an air gap, if he is comfortable with a high loop, regardless of whether the manufacturer recommends it or not, you can use it.

Dishwasher Air Gap Required

Bobber

New Member

Jadnashua

Retired Defense Industry Engineer xxx

Sponsor

Paid Advertisement

Gary Swart

In the Trades

Themp

Active Member

Jadnashua

Retired Defense Industry Engineer xxx

Tom Sawyer

In the Trades

Terry

The Plumbing Wizard

hj

Master Plumber

Similar threads