Thread: Dishwasher directly into a trap in the crawlspace

Can someone give me a hand with the verbiage on this one. This dishwasher drain hose runs through the sub floor and into the crawlspace. No air gap at sink. It then discharges directly into a waste trap. Has anyone ever seen this set up before and what would your statement be in the report?? Any input is greatly appreciated. Thanks

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Here is what the NC plumbing code says -

802.1.6 Domestic dishwashing machines.

Domestic dishwashing machines shall discharge indirectly through an

air gap or air break into a standpipe or waste receptor in

accordance with Section 802.2, or discharge into a
wye-branch fitting on the tailpiece of the kitchen sink or the
dishwasher connection of a food waste grinder. The waste
line of a domestic dishwashing machine discharging into a
kitchen sink tailpiece or food waste grinder shall connect to
a deck-mounted air gap or the waste line shall rise and be

securely fastened to the underside ofthe sink rim or counter.

Originally Posted by Shane Dredge

Can someone give me a hand with the verbiage on this one. This dishwasher drain hose runs through the sub floor and into the crawlspace. No air gap at sink. It then discharges directly into a waste trap. Has anyone ever seen this set up before and what would your statement be in the report?? Any input is greatly appreciated. Thanks

I do not have my code book handy, but I believe traps are in chapter 32 of the IRC and dishwashers are in chapter 27. Might be an older IRC.

Hope this helps...

See the PDF.

Best

Ron

Aside from everything else, every dishwasher manufacturer's installation instructions I've seen restricts the allowable length of the drain hose - 10 feet is typical - so most such installations I encounter (which usually involve kluging on some sort of drain hose extension) are incorrect even if other requirements are met.

Make sure they fix the leak in the dryer vent as well.

Hey... "flocked" pipes were "in" back then.

For verbiage - how about "improperly terminated to waste line"? Getting into discussion about air gaps and traps may not be very useful to clients since they'll likely have no idea what you're talking about.

Sometimes simple and concise works better than anything else.

As a side note,don't most modern dishwashers have an air gap at the washer itself ?

"As a side note,don't most modern dishwashers have an air gap at the washer itself ?"

Well, yes and no.
I don't remember an integral air gap being on the discharge line of a DW.
However most if not all DW do have an air gap on the supply line.
Also many DW do have an anti-back flow valve on the discharge line.
The problems are, you cannot tell if by looking at it if it has a BF or not,
even the manual may not help.

Here in Kentucky we're prohibited from quoting code in home inspections, so I don't happen to know which section requires the air gap (though I know good and well it's in there.) So what I would tell this buyer is "Dishwasher drain is unconventional arrangement which appears to allow possible backup of sewage into the dishwasher. Recommend having a licensed plumber install a proper drain for this appliance." Although it does not have the "umph" that a code quote would, pointing out the problem that following the code sidesteps is often helpful. (And people are REALLY squeamish about sewage. . .)