Could anyone shed some light on the old dishwasher drain tying into the kitchen sink drain pipe concept? I know that the dishwasher drain has to tie in higher up the drain so backups don’t go into the dishwasher but, what is the official practice here? The scenario is two sinks, one disposal and water everywhere when the sink backs up. Thanks…
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I think the plumbing code (IPC)wants the dishwasher discharge to either 1. pass through an air-gap mounted to the countertop or 2. the discharge line has to loop up and be attached to the bottom of the countertop so that waste water cannot be sucked back into the dishwasher. Here (in Seattle) only option number 1. is officially allowed.
Usually, the disposal has a fitting to which the dishwasher discharge can attach. Otherwise the dishwasher discharge attaches to a wye on the sink drain before the trap.
I'm not sure what you mean by "when the sink backs up". Does the dishwasher waste water back up into the sink or does the sink not drain properly? Is the disposal plugged up?
Both sinks fill with water and if the level gets too high (more than 2-3" of water) the bottom of the dishwasher fills with the water from the sink. If I remove the trap, the water from the sink drains immediately. The clog must be in the wall somewhere after the trap. The drain from the dishwasher comes up from the bottom of the cabinet (suspected problem) and goes into the connection on the disposal.
The drain from the dishwasher comes up from the bottom of the cabinet (suspected problem) and goes into the connection on the disposal.
As the previous poster said the drain from the DW should come from the top, not the bottom. Here we can use a high loop with no air gap but I think the air gap is good insurance.
In your case the clog is after the sink and the pig. Do you use the disposal a lot? I found that some of them grind the scrap especially meat into a paste thus creating a clog not far from the trap. Sending scrap down in small batches helps.
Another thing, I heard that if you drain the DW to the disposal, the detergent would corrode the disposal in no time.
As the owner of a duplex and the guy who then has to fix things that the renters don't bother to tell me about till it's too late, snake the pipe out and when using the disposal, run it with cold water only. Also run it longer. If you don't run it long enough, the stuff that was ground up sticks wherever it can and clogs the pipes, elbows and traps.You may want to check your local code for hookup to the disposal. Some places don't allow it, but I think more are changing that. Also, the dishwasher discharge hose is supposed to go out the bottom and up over the top of the dishwasher in a gentle curve to the air gap.
"I cut this piece four times and it's still too short."
Thanks again for the help: This is exactly the part I need to decipher.
As the previous poster said the drain from the DW should come from the top, not the bottom. Here we can use a high loop with no air gap but I think the air gap is good insurance.
I'm guessing that most dishwashers come with the drain tube mounted over the top of the dishwasher and that doing this prevents water from backing up from the sink drain to the dishwasher. (is this the same idea as a water level?) All I can see is the inside of the sink cabinet that has a hole drilled through the side wall about 2" from the bottom of the cabinet and attaches to the connection on the disposal. The dishwasher is so close to the cabinets and floor that I don't think it will ever be coming out without a major dismantle. I starting to get the idea that this will always be a problem unless the drain is remounted. Is it possible to simply add to the drain tube and bring the tube up to the bottom of the counter before going back into the disposal connection?
Sorry I didn't make it clear. The DW drain hose always comes out of the bottom of the DW, what the earlier poster and I was trying to say was the hose should then go to the the top of the cabinet just under the counter, then loops down and drains into a Y before the trap. In some area, instead of the high loop codes requires an air gap, that's to prevent any siphion action.
The way you described your situation I doubt that there is a high loop in the DW space if you see the discharge coming out at the bottom of the sink cab. So yes you are right it is like a water level and you end up getting water in the DW when the sink fills up.
Is it possible to simply add to the drain tube and bring the tube up to the bottom of the counter before going back into the disposal connection?
Yep, that would be the solution.
One more trick. If your disposal smells the best way to clean it is to put some ice in it and run it. Make sure you do it in small batches or the ice slurry will plug up the drain line till the ice melts.