View Full Version : External airgap for dishwasher

Apr 18, 2011, 08:03 AM
I am doing a remodel and would like to install an external air gap (ie, outside the wall of the house) in order to avoid installing the air gap through the new granite I am putting in. Does anyone have a configuration for this? I have heard it can be done but have not been able to find details. There is a very good earlier thread on this site that discusses the importance of an air gap whether code requires one. Thank you!

Apr 18, 2011, 08:08 AM
Before we get going you should really find out if the code applying to your area does or des not require one. Most of us simply install a high loop, if allowed.

Apr 18, 2011, 08:20 AM
Yes, it requires one. My contractor is hesitant to install an external air gap since he has never done one, but I recall reading about this option several years ago when I installed a dishwasher for a friend of mine. I think it basically involved running a high loop with 1 inch air gap outside the house, but I don't recall the details.
Thank you! Brad

Apr 18, 2011, 09:03 AM
I live in a climate, Illinois, where this would not be feasible if it were even allowed by code. Where do you live? Not sure which plumbing code your town follows but ask the inspector if he would allow such an air gap and how he'd like to see it for approval.

Apr 18, 2011, 01:47 PM
I wouldn't do it outside the house. I've seen some of them that match the countertop, particularly if tropic Brown and they are not objectionable. Fortunately, In GA, we can use a high loop.

Apr 18, 2011, 01:49 PM
Here's another thought. If you have a raised counter for eating, above the countertop, cut a niche recess, put the air gap in it and cover the opening with an ornamental tile held on with Velcro.

Apr 18, 2011, 05:35 PM
Thank you for the suggestions. Making a cover that matches the granite is a possibility I hadn't thought of. I live in Southern California, so it rarely gets cold and almost never gets below freezing long enough to cause pipes to freeze (of course, now that I have said this it will). Therefore, since the faucet requires 4 openings in the granite (2 valves, spigot, sprayer) my first choice would be to relocate it outside or perhaps in the laundry area.

Thank you again!

Apr 18, 2011, 07:05 PM
Ideally the air gap should be right above the dishwasher. Putting it too far away requires piping and friction loss from a fairly small pump. Can it go under the counter, above the flood rim of the dishwasher?

Apr 18, 2011, 07:12 PM
Do know the science behind it but often wondered why a air gap would not work immediately below the counter surface. Its just a vac breaker to stop siphoning and since a high loop works under the counter why not an air gap. Just wondering.

Apr 18, 2011, 07:27 PM
My thoughts too!

Apr 18, 2011, 08:21 PM
Wish Tom were here to explain it to us, he's been gone for 5 months and I miss his advice. Mark or Milo may stop by and tell us why under the counter would or would not work

Milo Dolezal
Apr 19, 2011, 12:15 AM
If you really want to avoid Air Gap on top of your counter top than install it (temporarily) in place of the sprayer. That's for Inspection purposes only. After Inspector signs the job off, toss the Air Gap, install Loop System under the counter top and install the sprayer in place of Air Gap.

To answer your question: Air Gap will work "...immediately below the counter surface...". However, any overflow from Air Gap will flood your cabinet. That's one of the reasons Air Gaps are placed on top of the sink.

Thank You... Milo

Apr 19, 2011, 02:47 PM
That's true and another reason why they are antiquated, just like places that won't allow AAV's Is there an AGL-Air Gap Lobby?