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manatra
Dishwasher Connected to Disposer

I just watched an episode and Richard replumbed a sink and disposer. There were three traps, one for the sink, one for the disposer/sink and one for the dishwasher. He remarked that he had never seen three traps before. He replumbed it to solve the owners problem of water standing just below the sink basket by combining everything into a single trap and also connected the dishwasher discharge into the disposer. Granted there is a provision for that connection HOWEVER you better check with your local plumbing codes. It may not be correct. For example in Chicago and the State of Illinois it states: Illinois Plumbing Code Sec 890.710 Food Waste Disposal Units .......Dishwashers shall not discharge into food waste disposal units. and again in Sec 890.770 Dishwashing Machines .... "Dishwashing machines shall discharge separately into a trap or tail piece of the kitchen sink and shall not connect to the food waste disposal unit.

No the poice aren't going to come and write you a citation but if you sell your home and your buyer has a home inspection, it will probably be an issue you'll have to repair.

Check your codes prior DIY repair.

dj1
Re: Dishwasher Connected to Disposer

What you wrote makes no sense to me. In California, we use one trap and the DW drains into the garbage disposer via an air gap - so that food leftovers go thru the GD and not directly to the drain. And that makes a lot of sense to me.

keith3267
Re: Dishwasher Connected to Disposer

Those codes would make sense if they applied to commercial dishwashers like in a restaurant or cafeteria, but not to private homes.

dj1
Re: Dishwasher Connected to Disposer

Keith, even for commercial kitchen, it makes no sense. If you bypass the GD, resedential kitchen or commercial, you let everything off the plates, dishes, cups - to the drain. How long do you think you can do that before you have a major clog?

Manatra, the code wording is sometimes conflicting. Read it again, in the right context.

keith3267
Re: Dishwasher Connected to Disposer

dj1, commercial dishwashers mount above the counter where home units mount below the counter. I'm not saying that draining a commercial dishwasher into a garbage disposal can't be done or should not be done, but I can see it requiring a separate P trap because of its height. I'm not sure why Illinois would not allow discharge into the GD after the P-trap, but maybe they have their reasons.

I really don't see it for home units though.

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