Dishwashers Drains and Garbage disposals
BillHartmann
| Posted in General Discussion on
Something that I have always wondered about.
Why feed the output of a dishwasher into a garbage diposal?
Now whatever material can get out of the DW through it’s realatively small pump and small discharge line should be able to go through the 1.5″ drain lines without chewing it up any more.
And the DW detergent is caustic and hard on the GD works.
So while run the DW drain through the GD.
Now on single bowl sinks there might not be a choice.
But on the common double (or tripple) sinks you can use a drain tailpipe with a conncection for the DW.
So why is the standard to connect the DW to ghe GD?
Replies
I am not sure you would call it a standard. I have heard that it is not a good idea because of the reasons you point out. I think it is just the easy way out in most cases. It does look like there should be enough flow to rinse things pretty well though.
i never do, see the post on dishwashers that arose this morning
ive seen dishwasher drains plumbed into almost every conceivable location, the most bizzarre was straight down through the floor and directly into a laundry tub in the basement!!, no loop upwards and the spray from the hose went everywhere!!
caulking is not a piece of trim
I think in some jurisdictions the disposal connection is regarded as equivalent to an air gap, or close enough, when the hose is looped high.
"I think in some jurisdictions the disposal connection is regarded as equivalent to an air gap, or close enough, when the hose is looped high."Some place may have that in their code or local practices.But in fact there is no difference between having the hose go into the GD or into the tailpiece.Same distance above the static level of the trap and same distance below the possible flood level of the bowl.
There is a difference. The disposal connection is fairly high above the regular drain level, and, unless the disposal is filled with water, there is effectively no way for any significant siphoning back into the DW to occur. If you just plug into a tailpiece, the DW could siphon back water laying in the bottom of the horizontal drainpipe.
If someone leaves unground stuff in the disposer and the DW drains into it, this could cause a clog in the DW drain or force the junk into the sink. Because my DW drains into the disposer, we make it a practice to run the disposer before starting the DW. Most new DWs have a food chopping feature as part of their no-pre-rinse-needed marketing. Seems to me that direct drain to tailpipe would be okay. Any potential siphoning would just make a mess in the kitchen -- not necessarily a health hazard like siphoning in the water supply.
I just checked mine. The distance from the bottom of the sink to the DW inlet on a GD is the same distance from the bottom of the sink to DW T connection on the tailpiece.So on the common sink with 2 equal bowls there is no difference.I have on with a smaller bowl with the GD and a larger deeper one so there is a difference in mine. But not in most.
OK, you're talking about the vertical tailpiece attached to a sink basin. I was thinking about the tailpiece that goes into the wall.Yeah, running the DW drain into a tap on the vertical coming out of a sink basin would be about equivalent to the DW connection. Well above the trap and any horizontal run between two basins, and the opening in the sink provides a decent vacuum break.
I don't know where you live, but in the N.E. that practice was banned 20 or so years ago. In the early days dishwashers were not as good as they are now. They sent the discharge into the disposal because people would not pre-rinse what they were putting into the dishwasher. You will still need a air-gap, safety issue. You can hook your drain where you want to. Luck.
A couple of years ago, when the kitchen was remodeled, I asked the plumber why he didn't run the DW drain into the GD. He said, here in Chicago, it's against code to do that.
Air gap isn't required here, so long as the DW install instructions say it's optional.When the DW drain line has the right loop and hooks into a disposal there is really no safety issue.
Unfortunatly, I connected my diswasher to my disposal instead of its own drain line under the sink - now I wish I knew how to change it back. We run the dishwasher all the time, but don't always make sure the GD is cleared first. Nice ugly backups happen then - uhg.
Any ideas on how to replug the plastic knockout on a disposal?
Rebuilding my home in Cypress, CA
Also a CRX fanatic!
Just drive a cork into the nipple?
>Any ideas on how to replug the plastic knockout on a disposal?
Yep. Rough up the inlet port ID with a fitting brush, then epoxy it, pushing the putty firmly into the hole while backing up with a spoon on the inside of the grind chamber. Unplug the grinder before you start!Regards, BillPS Use screws, instead ;-)