As the title says, when the dw drains, it was flooding the base cabinet. Seems like an easy enough fix, the drain line must be clogged.. I watched it is it was running, and when it drains, it just comes up over the drain vent into the cabinet... See pic

This is where it drains; The white line is the dw drain and it's pulled out and into a homer bucket while the dw is running. This black drain line connects up with disposal/sink drain line just to the right out of picture.




I was watching some youtube videos and saw a guy hook up the dw drain to the disposal.. I look at mine, and sure enough I have that inlet, and the sw drain line fits right on it, seemingly snug.




So... what is the difference here? Is a dedicated drain line required for some reason now? This certainly seems easier and less plumbing involved.

My house is 10 years old.

Should I consider this a temp fix and replace the drain line/trap (or shove a hangar down there to see if I can unclog it?) or is this good for permanent?Maybe it's a backflow thing?

the way it is now, I can see how water can get back into the dw.. even if I run the hose high, a full sink has a lot of head pressure.

Texker said:

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My DW line connects to the disposal inlet. Always has in all the houses I've owned.

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can you tell if there is some sort of backflow prevention method? If your sink drain is clogged, and the running dw dumps a few gallons of water in the sink, wouldn't it flow back into the dw?

Try and run the dishwasher w a cup of vinegar in a bowl. It will assist easing any clogged lines.

neAGle96 said:

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Try and run the dishwasher w a cup of vinegar in a bowl. It will assist easing any clogged lines.

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the clog is after the sw drain hose, but yeh I think I'll pour some draino down the 1.5" drain in the cabinet. It's an open top so can just pour it right in.

62strat said:

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Texker said:

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My DW line connects to the disposal inlet. Always has in all the houses I've owned.

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can you tell if there is some sort of backflow prevention method? If your sink drain is clogged, and the running dw dumps a few gallons of water in the sink, wouldn't it flow back into the dw?

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That's what the high loop is for.

https://homeinspectiongeeks.com/what-is-a-dishwasher-high-loop-and-why-do-you-need-one/

I just had an $18K claim due to the disposal fitting rusting and dumping water into the cabinet. While waiting on this to be settled, I have replaced the disposal and now have the drain line fitted onto the sink tailpiece.

Tony Franklins Other Shoe said:

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I'm assuming you didn't just replace the disposal. From experience, I forgot to punch out the knockout plug in that drain before when installing a new disposal. Also, I've had one or two clog up when we used the disposal much more before we started composting. I would start there and work back.

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I'm assuming that's not the case as it appears that the "required" hose clamp is missing from the white hose attached to the disposal. If the knockout was not removed then the white hose would have disengaged from the disposal and he would have most likely had a bigger issue of water in the sink cabinet! JMHO...

Good sleuthing.

OP
I would cut out every piece of that original setup. DW is supposed to drain into the garbage disposal like shown in later photos. You do need to add a hose clamp to keep it from popping off No plumbing should EVER drain into an open pipe like you've got there. That setup would overflow from a full sink of dishwater!

If no disposal then the plumber should have used a down pipe above the P-trap with a wye takeoff like they use for your AC drains.



Is this setup still under any new build warranty? If so you've got some rear end to chew in my opinion. Inspector (if there was one shoulda caught this too)

Rexter said:

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I just had an $18K claim due to the disposal fitting rusting and dumping water into the cabinet. While waiting on this to be settled, I have replaced the disposal and now have the drain line fitted onto the sink tailpiece.

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did they let it run ever day for a month?

Kenneth_2003 said:

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OP
I would cut out every piece of that original setup. DW is supposed to drain into the garbage disposal like shown in later photos. You do need to add a hose clamp to keep it from popping off No plumbing should EVER drain into an open pipe like you've got there. That setup would overflow from a full sink of dishwater!

If no disposal then the plumber should have used a down pipe above the P-trap with a wye takeoff like they use for your AC drains.



Is this setup still under any new build warranty? If so you've got some rear end to chew in my opinion. Inspector (if there was one shoulda caught this too)

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I'm glad you said something. I'm not a plumber, but the OP pics of the plumbing is very suspect/ fubar!

62Strat,

Can you post a pic further back that include the entire plumbing setup under your sink?

I'm still in disbelief that you have open plumbing down there.

Seems to be same concept as a clothes washer; drain into a standpipe.

https://forum.nachi.org/t/dishwasher-draining-into-a-standpipe/213985/2

half way down.. OP says he's in Englewood CO. which is south denver area.. very close to me.

I would add a hose clamp to the line from dishwasher, confirm there is no cap on disposal (mother in law had similar issue) and check the hose for less or cracks, I have seen where the dishwasher hose cracks from stress. Just a few suggestions

62strat said:

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Seems to be same concept as a clothes washer; drain into a standpipe.

https://forum.nachi.org/t/dishwasher-draining-into-a-standpipe/213985/2

half way down.. OP says he's in Englewood CO. which is south denver area.. very close to me.

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Both pics baffle me. I am NOT a plumber. The two pipes in the first pic are open? If so why?

The second pic has a white vent on the top? What is that for? Different state, different code(s), but now it's a curiosity thing.

just read the link. it's a regional thing. interesting, but again I am NOT a plumber.

Noticing the bowl there, I have these under my sinks.

Xtreme Undersink Mats

Your kitchen is either on the 2nd floor or the house is pier and beam and so these unfortunately won't work for you.

Gilligan said:

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62strat said:

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Seems to be same concept as a clothes washer; drain into a standpipe.

https://forum.nachi.org/t/dishwasher-draining-into-a-standpipe/213985/2

half way down.. OP says he's in Englewood CO. which is south denver area.. very close to me.

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Both pics baffle me. I am NOT a plumber. The two pipes in the first pic are open? If so why?

The second pic has a white vent on the top? What is that for? Different state, different code(s), but now it's a curiosity thing.

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isn't venting always required for a sink?

This is in an island. We have a basement, so you're right, 'second' floor with plumbing coming through the floor.
We normally don't have a bowl there.. that was just while I was disconnecting the drain hose from the disposal.

Plumbing has to be vented.

I have only had cooktops on an island, never a sink. starting to make sense now.

Just my luck.. I change this drain configuration to drain into disposal. it worked. No leaks or issues.

Until yesterday (just a day or two later), now my dw isn't draining after the cycle.. water is left in the bottom of dw, in the sump. I assume the pump went out??
I just ordered one on amazon and will swap it out to see if it works.

The dw ran the whole cycle, but has 1" of water in the bottom when it's done.

Gilligan said:

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Plumbing has to be vented.

I have only had cooktops on an island, never a sink. starting to make sense now.

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Yes. I missed that this is an island.

So the dishwasher is intermittently draining. Didn't flood the cabinet this time but stayed in the DW. Is the P-trap to the vent stack clear?

You did tap the knock out of the garbage disposal?

Gilligan said:

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You did tap the knock out of the garbage disposal?

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This.

Your p-trap is probably clogged on the other side. That is why it was backing up.
You have to knock out the plastic plug on the disposal, but you can't put it back, so be sure you want to keep it that way. Put a clamp on the line at the disposal. If the p-trap ever clogs on this side, it will back up into sink. Preferable in my opinion.

I would then cut and cap that whole second branch. It will backup there again if anything down stream clogs.

Gilligan said:

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You did tap the knock out of the garbage disposal?

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lol. I swore when I first hooked it up like this we ran a cycle with no issues.
Sure enough, I stuck my pinky in there.. yep it's solid!

How do I knock that thing out?
I think I want it like this permanently.

Tap it with a screwdriver and hammer. Get the plug out before you run the disposal.


***edit. Wrong link

You can do it with disposal in place.

ok.. i figured it was just like a junction box.

I think I have some worm clamps around in my homebrew tool box. Hopefully can get this done tonight or tomorrow.

62strat said:

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Gilligan said:

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You did tap the knock out of the garbage disposal?

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lol. I swore when I first hooked it up like this we ran a cycle with no issues.
Sure enough, I stuck my pinky in there.. yep it's solid!

How do I knock that thing out?
I think I want it like this permanently.

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It happens to the best of us. Just don't forget to fish it out of the disposal.

TexAg1987 said:

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Gilligan said:

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You did tap the knock out of the garbage disposal?

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This.

Your p-trap is probably clogged on the other side. That is why it was backing up.
You have to knock out the plastic plug on the disposal, but you can't put it back, so be sure you want to keep it that way. Put a clamp on the line at the disposal. If the p-trap ever clogs on this side, it will back up into sink. Preferable in my opinion.

I would then cut and cap that whole second branch. It will backup there again if anything down stream clogs.

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This is an island sink. Has to keep the vent stack or none of this will drain correctly. I WOULD remove that 2nd p-trap. it's no longer necessary.

Question for the group that are more smarter than me. How does this vent setup not fill that cabinet space with the foulest smell known to man?

Removing and capping the second p-trap branch was what I was referring to. The vent is the white cap thing.

Kenneth_2003 said:

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TexAg1987 said:

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Gilligan said:

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You did tap the knock out of the garbage disposal?

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This.

Your p-trap is probably clogged on the other side. That is why it was backing up.
You have to knock out the plastic plug on the disposal, but you can't put it back, so be sure you want to keep it that way. Put a clamp on the line at the disposal. If the p-trap ever clogs on this side, it will back up into sink. Preferable in my opinion.

I would then cut and cap that whole second branch. It will backup there again if anything down stream clogs.

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This is an island sink. Has to keep the vent stack or none of this will drain correctly. I WOULD remove that 2nd p-trap. it's no longer necessary.

Question for the group that are more smarter than me. How does this vent setup not fill that cabinet space with the foulest smell known to man?

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standing pipes have ptraps. This one drops down to basement joists, then a ptrap, then down to connect with main.

Kenneth_2003 said:

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Question for the group that are more smarter than me. How does this vent setup not fill that cabinet space with the foulest smell known to man?

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The p-traps are keeping the odor out of the cabinet. The valve at the top of the main drain is an air admittance vent. It is normally closed except when water is draining. Then it opens to let air in. Similar to a backflow preventer. Air in / no air out.