Island dishwasher plumbing

[swamp_fox]

New kitchen remodel with the dishwasher installed in the island right across from the sink. The sink drains into the vent stack, which extends below the floor (full basement) directly into the main septic line going to the tank. Here is an attempt at a 3D rendering.

Red is existing plumbing and green is my proposed path.







My plan is to add the plumbing for the dishwasher and drain it into the same vent stack as the sink, right before it enters the main septic line in the basement. The straight run from the dw to the vent tie in is about 6 feet.

Where should I place the P-trap for the dishwasher?

Do I need to add a air admittance valve? If so where?

Any unforeseen issues?

Thanks

 

[Terry]

If you can, I would add a P-Trap vented with an AAV in the cabinet near the dishwasher.
Is that a second dishwasher there?

 

[Sponsor]

 

[swamp_fox]

There is room to add an AAV in the cabinet behind the dishwasher, almost up to counter top height.

How does this look?
Should I add any clean outs?

 

[Terry]

An AAV goes "after" the p-trap to break the siphon there. It does nothing in the drawing. Nothing at all. The p-trap should be above the floor with a cleanout.
Also the dishwasher drain tubing should either have an air gap, or be looped as high as possible below the counter top.

 

[swamp_fox]

Is there anyway I can do this without and AAV?

Maybe a loop vent where both the waste line and the vent line go to the wet vent?

 

[swamp_fox]

Or this:

 

[Terry]

With an AAV you don't need anymore venting.

 

[swamp_fox]

Terry- the wet vent is already in place so that's where I'm planning to drain the dishwasher. Will both of the above diagrams work?

Not sure I am comfortable with the AAV over the loop, if he loop is functional.

 

[Terry]

I've done both.
Either the loop or the AAV will work. The loop doesn't need the AAV.

Here is another picture of a way to do that.

This one shows the combos that the inspectors like for the foot vent.