Dishwasher Draining - Pros/Cons of direct vs via disposal?

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lowefficiency

lowefficiency

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Hey folks, quick question-
For a modern dishwasher in a new installation, is there any particular reason why draining via the port in a disposal is preferable?

Typical benefits listed are that food waste gets an additional grinding, and that plumbing/installation is simpler because the disposal has the port on the side.

But it seems like that second grinding should be a non-issue, as a modern dishwasher either includes a grinder itself, or has a user-cleanable filter system to catch larger food items. The dishwasher discharge pipe is far smaller than the sink drain pipe it feeds into, and corrugated to boot, so I'm not understanding how this secondary grinding helps (or is necessary)?

On the flip side, feeding into the disposal means that the user must remember to run their disposal manually, at least periodically after doing dishes, as food scraps from the dishwasher will be deposited into the disposal... Whereas if the dishwasher discharged into the drain line directly (minding the proper trap/venting configuration, etc), this wouldn't be necessary.

Am I missing something, or is plumbing convenience the only real benefit?
 
I don’t know that there are any advantages to draining the DW via the garbage disposal vs the sink drain, but several years ago after repeated clogging of the disposal I took it out and installed a regular drain in its place. When I made this change I installed a tee connection to drain the DW through. I can’t see that the disposal connection was superior to the regular drain with the tee connection for the DW. I will say though I don’t miss that POS disposal at all. We compost our food waste and vegetable peels now. And we don’t use the DW anymore either. I can’t say that I miss either one of these appliances.

I know I know, I’m an AW heretic! But I’m old school. I like to have things done and not have to come back later on to unload a DW that may have one or two items that still need attention for some bit of food that didn’t come off in the wash and is now dried on. Plus, I never have to stop and clean some bowl, pan or whatever thats in the DW waiting to be run through a cycle, because I need that item for something I’m cooking.

Every time I leave my kitchen everything is clean, put away and ready for whenever I need it again. And I don’t find it to be anymore work than using a DW. Takes all kinds to make the world go around.

I still us the DW though, to store the drainboard, dish drainer and the compost container between uses, keeps these items out of sight until they are next needed.

Now I’ll duck and cover for the fall out.

Eddie
 
No fallout Eddie at least not from me

 

<span style="font-family: helvetica;">We are all different.  Think how boring it would be if we were all the same.  I'm old fashioned about some things but not the dishwasher.  There I am lazy as hell and want to put the dishes in and let them sit.  I am old fashioned about the microwave though.  I don't like the way it warms food.  I don't even use it to melt butter for a recipe.  I like to put a pan on the stove and warm the food.  I think it stays warmer longer too when you do it that way I really enjoy the process of getting out the pan, etc.  I may get some fall out over that.  </span>

 

<span style="font-family: helvetica;">Now for the topic of this thread.  The few homes I have built I had a separate drain installed just for the dishwasher.  I feel like that leaves the sink truly independent of the dishwasher.  There is no mess if I forget to run the disposal, etc.</span>
 
Thank you Ralph!

I agree with you about warming things some on the stove rather than in the MW oven, like meatloaf, meatballs and such. I think that often times the leftovers taste better than getting dried out in the MW. I’ve started doing this more and more myself. But one thing that the MW can’t be beat for is making puddings, pie fillings and white sauces in the MW. They never scorch or lump and don’t need the constant stirring that making them on the stove requires.

Eddie
 
noise , steam, and odors

Draining anything into a tap type drain
whether on a garbage disposal or a sink drain side tap-
that includes things like a dishwasher, a water filtration system, or even an attic mounted furnace/air conditioner condensate drain,
tend to make noise. That can be occasional 'tinking' noise from dripping or the fast discharge from a dishwasher. Sometimes the drain noise from a dishwasher makes more noise than the dishwasher when it's washing. Defeats the whole purpose of sound insulation and a quiet dishwasher.

Then there is the steam, odor, and as previously mentioned, particle build up. Who wants that. That can pit your plumbing fixtures.

Also, if one's sink drain should become blocked or back up, anything connected to it will not be able to drain and crud can then back up into the drain line of what ever that appliance is. yuck.

PVC fittings and piping are inexpensive. Its money well spent for proper, vented drains to each appliance. It's just like having dedicated electric circuits. We don't overload our outlets anymore.

As for those attic mounted furnaces and air conditioners, it's a pathetic job having a 1" line hastily run and dripping from a soffit outside. That's terrible. They need to have a proper 1 1/2" drain line connected to the plumbing system and preferably have a drain pan. [this post was last edited: 12/29/2021-16:03]

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Re: Reply #4

My dishwasher is connected to a vent thats on top of the right hand corner of the sink just like it was before when it was drained through the disposal. It drains more quietly without the DW. And I haven’t had to plunge my kitchen sink since I got rid of the disposal.

The last straw with the disposal was during the preparation of a holiday dinner for Easter. I had a house full of people and when I drained the potatoes into the disposal the sink backed up and in the middle of everything I had to get the plunger out, plunge the sink and then sanitize it since who wants to use a kitchen sink that the plunger thats been in the toilet was just used.

The very next day I bought the fitting just like in reply #4, went on You Tube and watched a few videos on how to make the conversion and in an hour it was done. When I had a new DW installed a year later the guy that installed it told me that I’d done as good a job as any plumber.

Eddie
 
I don't use a disposal either.
First if you're on septic, you're not supposed to as the fine particle can clog up the leach field. That's an expensive mistake.

Second, it's a disgusting machine. We put food stuffs in it, it tears it to bits and splatters the walls of the inside of the appliance. There, unless one can meticulously rinse all the gunk away (and no one really can), there it stays. Drying on, stinking, getting moldy, etc.

When I was a landlord all my properties had gds. They are cheap and easy to fix and replace, I'll give them that. I used to get ISE or Badger disposals at Menards for like $30. But several times all I needed to do, after dismounting it, is take the screws out and remove whatever stupid things were attempted to be put into it. One time I removed about 20 pennies that some how fell in.
Without the pennies in there it worked fine.
But they are Always layered with gunk and no one ever cleans those black rubber things that go in the hole. Even though they are removable and one could soak it in a bleach formula and clean it or put it in the dishwasher.

Third, I compost. Most of my food waste gets broken down naturally to make NEW fresh, fertile soil for my garden and pots.

I eat a lot of fruits & vegetables so there is a lot scrap. Apple cores, banana peels, pineapple waste, the undesirable parts of lettuce brocolli, tomatoes, etc. all go into a container in the freezer for at least 24 hrs.

When that's full it's simply dumped into another container, a bit of water is added, and the lid put on so it can defrost.

Then a couple days later it's layered inside my worm compost bin. A layer of shredded leaves is spread over it. The worms eat it up and turn it into black gold. And no fruit flies and no smell either. It's amazing.

The liquid that leaks down is harvested and poured on plants soil as fertilizer.

Now thats getting your money's worth on your food bills.
 
Eddie

"...watched a few videos on how to make the conversion and in an hour it was done."

I'm just curious, what did you do with the disposal?

Was it wired direct or did it plug into an outlet?
 
Bradfordwhite, I threw the disposal into the dumpster. It wasn’t hardwired, there is a dedicated outlet under the sink for the disposal. I believe it was a Badger, I bought it at a now defunct store named Yardbirds.

And you are so correct GD’s are filthy! Its next to impossible to keep up with cleaning out all the nasty sludge that builds up in them. I used to take out the rubber top regularly and clean it and reach under the edge an try to get out all that mess, glad I don’t need to do this anymore. As for the clogging, potato peels were the very worst culprit for that malady. I’ll never have another disposal again.

We use a plastic Maxwell House coffee can for the daily compostables. And we fill it tightly packed once a day then take it out to the compost bin in our HOA dumpster enclosure. If we had a vegetable garden we’d do what you do and use it that way. I think that putting all that crap into the pipes and using all that precious water to flush it down isn’t responsible in light of our current water shortage.

Another plus for no disposal is that there’s more storage space under the sink.

Eddie
 
Eddy, every newly-constructed house that my late husband and I moved into had a Badger disposal. It's common contractor quality. And yes, potato peelings would clog one of those things even if there were only a few. We learned to replace them with the better quality InSinkerator models with a much larger motor. But, I still don't put potato peelings, egg shells, or chicken bones and other "hard-to-digest" materials through.
 
I think that having the dishwasher drain into the disposal might help clean out the disposal and keep the odors down.  If you can catch when the DW is draining, turn on the disposal and it helps clean the upper chamber.  Might still have to clean the disposal manually but not as badly or as often.  I do use the disposal but most vegetable matter goes in compost, really just bits go down the disposal.
 
Maybe my reasoning is flawed, but I like the DW draining into the disposal in order to keep it flushed.  When the final rinse is set to sanitize, maybe it helps to keep the disposal clean?  I used to have problems with odor from the disposal until I switched the DW to drain into it.  I haven't noticed odor since then.
 
I'm A Disposal Fan

I've got a standard 1/3 HP Insinkerator model 1-83. It's been in the house before I bought the house 13 years ago. I've never had any issues with odors. When I need to use it, I simply run some water and flip the switch. In 1 sec everything is gone. No food or anything is left in the disposal. That's just been my experience.

On the other hand I've seen air gaps get clogged and become a maintenance hassle. Like seen in this video.

 
My kitchen sink has a vent on the top right and the dishwasher drains through the disposal....I haven't had any clogs from the dishwasher but I have had clogs in the past from actually USING the disposal itself....so I stopped using it..When the clog happened, I thought I was going to have to call a plumber because no amount of plunging was working...it was then I discovered a youtube video. In the video they covered the vent before plunging....that worked.

The garbage disposal does get nasty!! Even if not used...Every few months I put rubber gloves on and pour cleanser down in there and scrub the sides underneath the rubber....It's so gross... and even with me keeping the sink clean daily with hot water......the disposal area still will get gross over time on its own
 
Re: Reply#15

Mark, I discovered the trick of covering the DW vent with a wash cloth when plunging on my own, as when I’d plunge the GD water would come out of the vent. I also found that putting the GD stopper in the drain of the sink next to the GD side helped make the plunging more effective. Sounds like your experience with the sludge in the GD and having to frequently clean it out mirrors mine.

To each his own, but I lived most of my life without a GD and I don’t miss having one a bit. I imagine if I’d had a power powerful and expensive GD then maybe I wouldn’t have experienced the frequent clogging of the kitchen sink drain. However, replacing the GD with a conventional drain solved the problem. Haven’t had a clogged kitchen sink since nor have had to clean out a nasty, sludge filled GD.

Eddie[this post was last edited: 1/1/2022-13:19]
 
I bought a round toilet brush at dollar tree....it perfectly fits down into the disposal.  I sprinkle Comet on it, stick it down and go to business.  Plus, we regularly pour a little bleach water down.  No smells!  Back when dishwasher detergents all had chlorine, my mother's drained into a disposal.  It never smelled either...kept it cleaned out.
 
The problem with the disposer is not so much the grinding plate being dirty. When ever one pours something into the disposer or a dishwasher drains into it, it flushes the plate and supposedly that which is beneath it.

The main stink problem is the walls of the chamber.

When the plate grinds, it throws gunk all over the chamber and the walls get covered.

If people could see how bad it is, most would surely clean up the mess.

If ever anything greasy has been put down there, that grease can get on the plate, under the plate, on the walls.... and gunk will stick to it. No household chemical cleaner is going to remove layers of grease. That needs to be scraped off.

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