Dishwasher drain: Before of after the P-Trap?

[Joacchim57]

I ordered a new Whirlpool dishwasher to replace our 25 year old Maytag. In preparation I went online for the install manual and see the drain hookup is supposed to be before the P-trap, but I'm finding that mine was hooked up after, probably because of the short pipe lengths under the sink.

We've never noticed a smell of sewer gas so I'm hesitant to replumb the drain piping. What do you guys think? I know, the photo looks like it needs to be redone, but... My first post, btw.

 

[MicEd69]

That is a big NO!!! While there is some water left in the bottom of a dishwasher after draining, it is not designed to be a trap. And there could be sewer gases coming into your dishwasher. EVERY drain in a house that goes into a sanitary sewer MUST go through a trap. The toilet has a built-in trap, but everything else needs to have a P-trap to prevent sewer gases from entering the house.

Big time code violation and possible health issue.

 

[Joacchim57]

Attached photo shows how I plumbed it. I don't like the flex pipe but couldn't figure any other way to get everything lined up.

 

[Twowaxhack]

Center outlet waste would’ve solved many issues.

 

[Joacchim57]

That was how it was originally piped (see earlier photos) but I could not find a cross tee with a top connection for the dw drain. And this one had to be mounted to one or the other sink, no way to attach in between. Works for now...

 

[Twowaxhack]

You would’ve used a center outlet tee with a slip joint dishwasher tailpiece between the tee and the pTrap in the vertical position.

 

[TomFOhio]

It looks like the drain water from the DW is going to go straight through that tee unless it has a baffle in it.

 

[Joacchim57]

There is a baffle inside.