Adding a Dishwasher Standpipe

Users who are viewing this thread

SPSHF15

New Member
Messages
4
Reaction score
2
Points
1
Location
California
Hello All,
I would like to NOT have an air gap installed in the kitchen island mainly for aesthetic reasons. I live in California and my local building department said that I cannot use a high loop or AAV. I have been doing some searching through the forums here and it seems that I could add a standpipe with a dedicated p-trap for the dishwasher.
The current setup is in the first picture with the dishwasher located to the right.
Note the air loop has a 2" pipe up to the T and below the clean-out with a 1.5" loop.
1) Can I add another 2" T to the left side of the loop and just have two stacked Ts with one going to the sink and one to the new standpipe?
2) Is there a required distance between the Ts?
3) Is there a required height of the standpipe? i.e. like a vertical rise or rise above the sink base? To me it seems that with a dedicated p-trap the sink is decoupled and I don't to make the standpipe higher than it needs to be should I need to clean it out.

I'm thinking that I want to change the T that is in there now anyway because the plumber and the electrician didn't seem to communicate. I'm open to other ideas short of adding an air gap to the countertop.

UnderSink.jpg
 

breplum

Licensed plumbing contractor
Messages
1,074
Reaction score
402
Points
83
Location
San Francisco Bay Area
Stand pipe is a terrible idea and invitation for flooding.
1. Your current drain is not to code and should be changed because the flex drain extension is not UPC/CPC approved. I'd use no-hub couplings to cut out the existing tee and re-plumb the current p-trap properly.
1A. No, you can't by code put a tee in on the left.
2. Put the air gap in for inspector, then change out for high loop after inspection and put a soap dispenser or cap the hole. While noting that there is a potential health hazard in not having a DW air gap.
 

Terry

The Plumbing Wizard
Staff member
Messages
29,701
Reaction score
3,257
Points
113
Location
Bothell, Washington
Website
terrylove.com
The left side is the vent, and you can't put the dishwasher drain into the left side vent.
The picture below is a flipped version of what you have.

island_sink_bert_polk.jpg
 

Reach4

Well-Known Member
Messages
36,030
Reaction score
3,778
Points
113
Location
IL
Your disposal will have an input (blocked by knockout initially), intended to accept dishwasher drainage. That drainage would should be thru an air gap by code. Air gap is usually mounts into hole in the counter. Is your dishwasher input going to be inspected? Then you would just have to figure out how to have a trap without the flexible section. Rotating the disposal could face the output in a better direction. There is slip joint stuff that can work for you, including using a straight discharge tube, and then going down via a slip joint elbow to your trap input.

If you look up "Disposal Kit" you will see a collection of parts, most of which you don't need. But it could show you, for example, what a straight discharge tube looks like. So once you figure out what you want, you can buy pieces ala carte if you can find them.
 

Terry

The Plumbing Wizard
Staff member
Messages
29,701
Reaction score
3,257
Points
113
Location
Bothell, Washington
Website
terrylove.com
Your disposal will have an input (blocked by knockout initially), intended to accept dishwasher drainage. That drainage would should be thru an air gap by code.
He has the dishwasher draining into the disposer now using an air gap. The inspector wants the air-gap though.
Even if it doesn't drain to the disposer, the inspector is looking to see the air-gap being used.
Breplum mentioned doing a little work to change that after the inspector leaves, some contractors do that for homeowners that don't like seeing them on the counter. Not code, but I have seen it done. The high loop helps with that. The last Bosch dishwasher I installed had a very long drain hose. I used the air-gap anyway.

sink_dw.jpg
 

SPSHF15

New Member
Messages
4
Reaction score
2
Points
1
Location
California
Thank you all for the feedback especially on that flex section which I will remedy.
I now understand I can't put the second T on the left side, but can I stack them on the right side of the loop?
Even if I could put a standpipe in, I suspect the inspector might have a problem with it if he/she doesn't see the countertop air gap. Does code allow the standpipe?
In the end, Breplum's advice is probably the most rational and what I'll do.
 

Reach4

Well-Known Member
Messages
36,030
Reaction score
3,778
Points
113
Location
IL
If he wants to see an air gap, won't he also want to see it mounted thru a hole in the counter? Any hole in the counter that you could repurpose to an air gap, at least temporarily?

If you add a hole, you could put in a combo dispenser/air gap.

air-gap-lotion-dispenser-westbrass.jpg
air-gap-lotion-dispenser-westbrass-spec.jpg
 
Last edited by a moderator:

Jeff H Young

In the Trades
Messages
5,728
Reaction score
1,281
Points
113
Location
92346
Using a stand pipe doesn't negate the need for an air gap. shoving the hose down a stand pipe isn't legal either
Us People in California should have a better way of complying I suppose the Johnson fitting that either was or is used in WA would work. Don't know if you guys still use them or if you do if its on nearly all jobs?
A lot of cheating goes on here as Breplum says I've done it but always tell them its illegal and why. I think its kinda over kill but its an opinion I think it might have a small chance of germs
 

Terry

The Plumbing Wizard
Staff member
Messages
29,701
Reaction score
3,257
Points
113
Location
Bothell, Washington
Website
terrylove.com
It can depend on the dishwasher as to whether the water from the kitchen sink winds up back in the dishwasher. That's really the purpose of the air-gap.
A friend of mine used to run her dishwasher every four days, and by the time she did the bottom would be filled with dirty and smelly water. Yes, that's what she washed her dishes with. I added an air-gap and then after four days, the bottom of the dishwasher was still dry and clean. No more murky water from the disposer getting into her dishwasher.
 

Jeff H Young

In the Trades
Messages
5,728
Reaction score
1,281
Points
113
Location
92346
It can depend on the dishwasher as to whether the water from the kitchen sink winds up back in the dishwasher. That's really the purpose of the air-gap.
A friend of mine used to run her dishwasher every four days, and by the time she did the bottom would be filled with dirty and smelly water. Yes, that's what she washed her dishes with. I added an air-gap and then after four days, the bottom of the dishwasher was still dry and clean. No more murky water from the disposer getting into her dishwasher.
Yep thats where the high loop drain hose is supposed to protect I dont nessesarily agree but thats the theory as far as I know no dishwasher is exempt from requireing air gap in our code Ive heard people think that some fancy models dont require but I dont buy that
 
Top
Hey, wait a minute.

This is awkward, but...

It looks like you're using an ad blocker. We get it, but (1) terrylove.com can't live without ads, and (2) ad blockers can cause issues with videos and comments. If you'd like to support the site, please allow ads.

If any particular ad is your REASON for blocking ads, please let us know. We might be able to do something about it. Thanks.
I've Disabled AdBlock    No Thanks