Is this triple kitchen sink DWV layout OK?

[john811]

I’m in Washington state and adding on to my kitchen and want to install a 3 compartment sink. I’ve looked all over but haven’t been able to find a typical DWV layout for a 3 compartment sink with a disposal.

1. Will the attached layout work?
2. Additionally, is there a better way to do this other than how I’ve laid it out? Just a crawl space below, so I can add a second 2” line coming up from below the floor and tie in the vents above if it provides a better layout.
3. I've read about the trap arm length requirements - The distance between the 1st and 3rd sink is about 25” - Is the trap arm length ok?
4. Lastly, the sink compartment on the left is the one that will be used the most for washing dishes, etc. so I located the p trap with a straight shot from that sink assuming that's the best location - correct?

Thanks in advance for your advice!!

[Doherty Plumbing]

I would be running 2" on a 3 compartment sink.... in fact up here in Canada it would be code that it be 2".

[Peter Griffin]

It's not code, but I would go with 2" also. In fact, even without a disposer we pipe all kitchen drains in 2" now.
The easy way to pipe that 3 bay is to dump the disposer into a separate trap from the other 2 bays

[hj]

The problem with your drawing is that the disposer is usually directly in the path between the two sinks so you have to "jog" around it to get from the left drain to the right one. There are several ways to do it, depending on what the status of your remodel is, i.e., can the drain in the wall be revised, or how much room is in the cabinet.

[john811]

On the particular sink I am looking at, the middle sink drain with the disposal actually is offset by about 7 inches from the two main bowl drains, so I will be able to connect the two main bowls in a straight line and the outlet from the disposal will tee in wherever it lines up.

[hj]

In that case, your drawing will work. it will just be a bit "spindly" because of all the slip joints. I usually make two or three outlets in the wall so that the drain setup is simpler.

[jc60618]

Good thing you can get away with draining the dishwasher into the garbage disposal knockout. Around here we have to use a wye tailpiece for that connection.

[dcelite]

In my code book the trap must be under the center compartment.

[hj]

"I'm from Missouri, SHOW ME". That would be an almost impossible situation since the disposer is ALWAYS in the center sink well.