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Thread: Air gap requirement for dishwasher

  1. #1
    DIY Junior Member BlackToe's Avatar
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    Default Air gap requirement for dishwasher

    I'm plumbing my new kitchen island, and I'm about to install a new Jenn-Air dishwasher. It has a built-in "high loop" on the side of the unit, and I plan to connect its drain hose to my disposer.

    The inspector told me (in a voice mail) that all dishwashers require an air gap per WA state code.

    Does the loop on my dishwasher meet the code requirement? If not, can I create an air gap just under the counter so I don't have to mount some ugly thing on top of my sink?

    Last edited by Terry; 10-24-2008 at 05:23 PM.

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    Moderator & Master Plumber hj's Avatar
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    Default loop

    It depends on your local ordinance, but an air gap under the sink, in the cabinet, would be a positive way to flood the area.

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    Master Plumber nhmaster's Avatar
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    No, the high loop is not an air gap. You need to install one on the sink

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    DIY Junior Member BlackToe's Avatar
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    Quote Originally Posted by nhmaster View Post
    No, the high loop is not an air gap. You need to install one on the sink
    Thanks for the replies, guys. I asked a friend who lives in a newly-built home nearby, and she said there is no air gap in her sink. She *did* know what an air gap is, so I don't think she just didn't see it. Not sure what that says, as her house obviously passed inspection. At any rate, I want to do things correctly, so I'll plan on installing one in my island.

    Here's a follow-up (possibly dumb) question: I've got a stainless undermount sink, which I assume means I have to mount the air gap on the countertop. If the air gap leaks, what is the best method of making sure it leaks in to the sink? Do I just mount it close and aim it at the sink?

    If you're bored and looking for something to critique, take a peek at the drain plumbing I did in the island (note: the plywood countertops are TEMPORARY until we build concrete countertops):
    http://slavetothehouse.blogspot.com/...eed-water.html

    Now, I'm not a plumber, so don't rail on me or anything. I'm *trying* to do everything right, but I *do* make mistakes sometimes. If you see any glaring errors in what I did, I'd appreciate a heads-up because I'll be calling for my final inspection after I run my supply lines tonight.

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    Forum Admin, Expert Plumber Terry's Avatar
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    If your friend has a new home, they may have a "Johnson Tee" for the air gap. If that is the case, you would see a 3/4" PVC cap through the siding with a 1/4" hole drilled in it. It would be higher than the counter height.

    The waste fittings for a kitchen sink are 2" up to the Santee, then it can transition to 1.5" for the trap arm.
    Water supply tees are not used.
    They have to be waste fittings.

    The sink also uses a 2" clean out.

    Last edited by Terry; 08-28-2010 at 10:22 AM.

  6. #6
    Plunger/TurdPuncher kingsotall's Avatar
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    2 p-traps far superior than one┐ Water dripping into p-trap┐ Is the new faucet already leaking┐ I don't get it.

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    DIY Junior Member BlackToe's Avatar
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    Quote Originally Posted by kingsotall View Post
    2 p-traps far superior than one┐ Water dripping into p-trap┐ Is the new faucet already leaking┐ I don't get it.
    I pretty much followed the ideas presented here: http://www.polaris.net/palmk/GDplumbing.html

    In short, the two traps create less restriction than a tee, and the two 45's make for a less noisy drain. I don't claim to be any kind of expert, but this made sense to my plumbing-tarded mind.

    I ran the supply lines for the sink and dishwasher tonight, and, fortunately, there were no leaks.

    Quote Originally Posted by Terry View Post
    If your friend has a new home, they may have a "Johnson Tee" for the air gap. If that is the case, you would see a 3/4" PVC cap through the siding with a 1/4" hole drilled in it. It would be higher than the counter height.
    This sounds a lot like what was on the exterior of our house before we tore that wall out for our addition. Out of curiosity, I'm going to have to go have a look at my friend's kitchen.

    Quote Originally Posted by Terry View Post
    The waste fittings for a kitchen sink are 2" up to the Santee, then it can transition to 1.5" for the trap arm. Water supply tees are not used. They have to be waste fittings. The sink also uses a 2" clean out.
    If I'm understanding you correctly, I need to:

    1) Make all the Sch 40 stuff 2" instead of 1.5" (the vertical pipe, tee and wye)
    2) Replace the slip tee with a waste fitting santee

    I guess that makes sense, and shouldn't be too much work or money. That's what I get for going to Home Depot -- I'm so happy when I can find ANYTHING there closely resembling what I need that I grab it without thinking. I found out the other day that Lowes has a WAY better selection of plumbing stuff.

    Thanks a lot, I totally appreciate your help. If you ever need any advice about coding or diving, I hope I can repay the favor. =)

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    In the Trades Gary Swart's Avatar
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    This is a question for King So Tall. Why are your question marks (?) upside down in your post? I've noticed it before, but never took time to ask?

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    Plunger/TurdPuncher kingsotall's Avatar
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    A plumbing supply house would have a WAYYYY better selection than any big boxer.

    Gary, I don't have a good explanation why!

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    DIY Junior Member BlackToe's Avatar
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    Quote Originally Posted by Terry View Post
    The waste fittings for a kitchen sink are 2" up to the Santee, then it can transition to 1.5" for the trap arm.
    After sleeping on this, I think I misunderstood your answer. Are you saying the vertical run needs to be 2", up to and including the Santee, but I can transition to 1.5" after that? Or does the wye have to be 2", also? I think I'll probably just replace the wye with 2", anyhow, so I don't have to add a reducer, but I'd like to understand the underlying concepts so I can be a little smarter for the next project.

    Quote Originally Posted by Terry View Post
    The sink also uses a 2" clean out.
    My cleanout is directly below the floor at the end of the 2" ABS run. You can kind of see it here, on the tee:



    Do I need another cleanout somewhere else?

    Quote Originally Posted by kingsotall View Post
    A plumbing supply house would have a WAYYYY better selection than any big boxer.
    Can you recommend a supply house in the Renton/Tukwila area?

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    Master Plumber Redwood's Avatar
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    That cleanout although required is not all that functional...
    I wouldn't use it!

    I would put a cleanout below the sink just above the traps.
    This way you can run water with the snake in the line.

  12. #12
    DIY Junior Member BlackToe's Avatar
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    Quote Originally Posted by Gary Swart View Post
    This is a question for King So Tall. Why are your question marks (?) upside down in your post? I've noticed it before, but never took time to ask?
    You mean this - "┐"? Try typing ¿.

    It's an HTML encoding issue. It could be caused by using a language other than U.S. English on the computer. More info at http://tlt.its.psu.edu/suggestions/i.../codehtml.html

  13. #13
    DIY Junior Member BlackToe's Avatar
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    Quote Originally Posted by Redwood View Post
    I would put a cleanout below the sink just above the traps. This way you can run water with the snake in the line.
    You mean *in-line* before the traps, or just somewhere higher than the traps (like maybe below the AAV)?

    I'm really not too concerned about this cleanout for two reasons: 1) I'm 37, and I've never had a drain pipe clog in my homes, and 2) if I get a clog above the ABS, I can loosen the rubber sleeve and yank the PVC out in about one minute.

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