Dishwasher airgap

Hi-

We are about to start a big kitchen remodel. We're installing slab granite and an undermount sink. Our plumber, when he came to scope the job, said he could remove the airgap we have now for our dishwasher and just route it through the disposal. Is this right? I don't want to end up with something that's not to code and would require drilling a hole in the granite after the fact.

Thanks in advance!

Yes, you just loop the drain line up to the top of the bottom of the counter top then into the GD.

Unless your local code requires it, the normal way to hook up a dishwasher is through the disposal. The hose must be routed up as high as possible under the cabinets/counter, then down to the disposal. My unprofessional experience.

Thanks. So it sounds like it's OK.
I appreciate the advice!

Why are or were air gaps put in dishwasher lines?

Mine has the line from the dishwasher to a air gap then to the disposal can I eliminate the air gap and use the hole in the sink for something else?

Thanks.

Some areas require them, some don't. I doubt if many are installed where they are not required by local code. As previously described, the drain hose must be looped. The usual method is to attach it to the underside of the counter.

Removal of an Air Gap is basically removing the seat belts out of your car, not a wise choice. High looping is only for looks, as water takes the path of least resistance. Meaning, wastewater will travel back through dishwasher discharge before it overflows the sink. Granite sinks with their thickness guarantees a lower high loop. Visit numerous plumbing forums and search under keywords of dishwashers with wastewater in bottom. A perfect example where a clogged sink sent the wastewater back into the dishwasher. An area that you expect to produce sterile eating/drinking utensils after its use. Having airborne bacteria fermenting in a closed/hot/moist area is a breeding ground for disaster. Children bear the brunt of this unknowing hazard caused by their adult parents. Too much assumption put on the guarantee that the dishes are clean, when they actually are not when a cesspool of waste is in the bottom of the dishwasher.

You must find out what your code requires. You may not be able to do away with it. We lived for many years without airgaps, or backflows on sprinklers. But ^%@# happens. Air gaps are inconvenient on granite sinks, but if you must have it, then that's the end of the story.

RUGGED said:

Removal of an Air Gap is basically removing the seat belts out of your car, not a wise choice. High looping is only for looks, as water takes the path of least resistance. Meaning, wastewater will travel back through dishwasher discharge before it overflows the sink. Granite sinks with their thickness guarantees a lower high loop. Visit numerous plumbing forums and search under keywords of dishwashers with wastewater in bottom. A perfect example where a clogged sink sent the wastewater back into the dishwasher. An area that you expect to produce sterile eating/drinking utensils after its use. Having airborne bacteria fermenting in a closed/hot/moist area is a breeding ground for disaster. Children bear the brunt of this unknowing hazard caused by their adult parents. Too much assumption put on the guarantee that the dishes are clean, when they actually are not when a cesspool of waste is in the bottom of the dishwasher.

Click to expand...

Isn't that more from having a busted dishwasher pump than from a clogged sink line?

No. Reference Plumbing Principle #15 Has nothing to do with a failing pump. It can happen but most times it is linked to a clogged drain as I mentioned. The surprise was always waiting in the dishwasher with the thread starter "thinking" the dishwasher was broken. Removal of the clog and installation of an Air Gap prevents that situation from ever happening again.


Here's one on a high end granite top/undermount sink in my area. Told the customer of the possible health hazards, the customer didn't question the simple logic involving the possibility of someone getting sick, opted for the Air Gap. Just like anything, you get used to the way something looks.




Now remember that this pic was immediately after install, the customer had a brass top come in for this Air Gap. When I came back months later to install a faucet for the customer on a laundry tub, I veered over and noticed the top covered with numerous items and nicknacks, normal stuff found on countertops. It basically blends right into the scheme of things and forgotten.

air gaps are a waste of time and money

they are simply
not necessary, in our area the mid west,
they are not required and never have been.


so their are literally millions of people without them and
they have never had a problem, and probably never will

in fact the AIR GAP is usually the problem a lot of times
they leak and spit out water all over the place and have
to be changed out...

and I can only figure it
is something to give the plumbing inspectors
something to gripe about when they dont
see one.....in other areas of the country


the garbage disposal has an opening for the dishwasher,
they are all made that way for a reason,
and its very functional and pratical....

and most of the time the dishwasher has a hose that is already
ran high ehough on the side of it to function propery for an air gap...


all that is necessary is to run the pipe as high as
possible under the sink and hook it to something to hold it
in place.....


it will work for maybe 40 years,
so what more can you ask.

I've been told by numerous plumbers from varying states that Kentucky enforces the strictest codes across the land. I've found this to be true by how many states, including nearby Ohio with the lack of enforcement of such items. Let me say that instead of trying to build a million proving points on its effectiveness to protect human life, I suggest that plumbers, DIY'rs and all who read this post understand that logic isn't always written to make us do things by the force of hand, and I mean code.

Anyone that has had the chore to pump a swimming pool by taking a garden hose and filling it with water and taking it over the ledge to start it running to remove the water, knows that I just described the drain line to a dishwasher. No interruption to prevent contamination. It must be true that all plumbing code books are not created equal, my book specifically states in principle #15 that at no time do you direct connect to the waste system.

Doesn't matter to me if you do things right or wrong, I'm just here to educate the viewing public to protect yourselves, like I do in numerous parts of the world wide web with my knowledge. Codes are written, removed, altered, changed on an ongoing basis. Some states are laxed on codes that shouldn't be, some codes I do not agree with. This topic on Air Gaps is a simple one, health protection. The only one that counts.

air gaps

if your dishwasher pump fails to functioin
and your dishwasher fills up with dirty water,

what have you got???? A pond of stagnant water.

And it never made it through the valuable air gap



personally I feel its just overkill for overkills sake.

If you feel you are protecting the health of the
nation, so be it.....




what about stopped up kitchen drains??

where will it all end????


with such high risk of potettial danger here
maybe we should outlaw dishwashers all together


ohhh, I am sorry, I should really just let this go,

but its so much fun

I would think a one way valve would be more effective than an air gap at preventing back flow. Growing up I never knew that was an air gap, I just thought that was how the dish washer drained! Water spewing out over the sink was great fun to watch! Do some of the disposals contain a back flow valve or integral air gap?

tjbaudio said:

Do some of the disposals contain a back flow valve or integral air gap?

Click to expand...

No, but some diswashers today do have a check valve. Almost all DW today have a high loop bulit into the discharge. None of these things trump a local jurisdictions air gap requirement,

air gap

I have used a loop just like most other plumbers and for the reasons as others have pointed out.

What I hear RUGGED saying is that when certain conditions exist, a near perfect vacuum can exist and the contaminated water can be pulled back into the community water system and affect everyone. If your on a well it can do it there and affect only you.

Check valves can fail also.

dw

1. Dishwashers have always had check valves in the drain.
2. I have not seen any DW's with a drain hose coming out the top or looping up to the top. Most come directly from the pump, through a hole at the bottom of the cabinet and then up to the counter top.
3. A DW drain connected directly to the disposer is not "connected directly to the drain system". That would only happen if the DW had its own trap, or other connection, and was hooked right to the drain pipe. THAT could create a backflow or siphon condition more serious than connecting to the disposer.

Jimbo stated the facts, to the tee. And yes, they do high loop the drains on the sides of the dishwasher now, the reason for interconnecting corrogated tubing (2)

Check valves can fail instantly, just like plumber1 stated with something as simple as a toothpick, chunk of food, shrimp tail. Lost all of its protective features, you cannot access it easily to clear it, springs can and will fail. Anytime you offer the free atmosphere (Air Gap) as a way to prevent backflow, it is a remedy for a simpler protection.

plumber1 I was referencing to wastewater from the kitchen sink, not on the potable water side of protection. That possibility can happen but my point in Air Gaps are to keep wastewater, meaning everything that DWV system has in it, like human feces, laundry wastewater, detergents, wastewater from sinks, tubs, showers OUT OF THE DISHWASHER. These are contaminants that affect human health. Very rarely do you see the kitchen sink on a separate line....other than gray water systems. Lots of bathrooms above kitchen sinks or one floor above, all tied together somehow or another. But what you mentioned is possible with the reversal of contaminates heading back towards the dishwasher in "certain" chains of events.

As to your response hj, It is not true that all dishwashers have check valves in them, I can simply deter that logic by buying OEM replacement hoses for older model dishwashers. Jimbo is correct in what he is stating.

In regards to high looping already being done on the dishwasher itself, Jimbo is once again correct. Proof is waiting at your local appliance store, start with Whirlpool, Kenmore, Jenn-Air models. Not all, but a good deal of them are making dishwashers this way. I've installed 3 in the past month, all three had dual hoses with one connection underneath, one to the drainage system.

A DW drain connected directly to the disposer is not "connected directly to the drain system".

Find me 10 plumbing inspectors in individual states that will sign off to that statement. Even better, have them call me.

The grinding chamber of a disposal beneath the flood level rim of ANY sink is not considered a threshold for the "CL" Critical Level.

If you use a separate stand pipe and trap do you still need the air gap above the counter or is the gap between the pipe and the drain tube good enough like it is in a clothing washer?

Also does this pipe need to be 2" like a washer or is 1.5" the right size?

Since the discussion is here I may as well get the info for next summers kitchen remodel

If you can have the DW drain to a trap and san T AND have an air gap of 2" it will work. The reason for the air gap being on top of the counter is when the drain is connected to the GD the flood rim becomes the top of the sink. If you drain to a trap and have a air gap the flood rim becomes where the trap would over flow, 2" below where the DW drain stops. That said, if it is under the counter and becomes stopped up you will have an entire DW cycle of water under your counter and on your floor and if the sink backs up you may have the same problem, depending on where the clog is. The other way (air gap on counter) or loop under the counter at least the sink would fill B4 it overflowed.

If it were me I would loop under the counter unless local code requires the air gap on the counter.

This is just a guess but I'll bet 3/4 of all GDs are looped under the counter.