Replacing laundry/kitchen branch dwv line

[saf-t scissors]

The house currently has one 1-1/2" dwv pipe that picks up both the kitchen sink and the washing machine. The plan is to upsize the existing line and add a new utility sink in the laundry. I know that the washer, kitchen sink, and utility sink should each be 2". Off the top of my head, I think the code allows for all three to share a single 2", but I need to check tomorrow to be certain.

If the code says 2" is acceptable, is it wise? Seems like the main line should be larger than that. Total horizontal run is less than 30ft before it wyes into a 4in horizontal line.

Also worth mentioning that the current system has no vents, save for a (relatively new) AAV under the kitchen sink (b/c the washing machine was sucking the kitchen trap dry). The new piping will put 1-1/2" vents at the utility sink and the washing machine. The kitchen aav will have to remain for now.

Thanks.

 

[FloridaOrange]

Code issues will depend on your location, please post city/county/state.

 

[Sponsor]

 

[hj]

drain

As a practical matter, you will only be using one of those drains at any one time, so what difference does it make as long as the pipe is adequate for any one of them?

 

[FloridaOrange]

As a practical matter, you will only be using one of those drains at any one time, so what difference does it make as long as the pipe is adequate for any one of them?

Florida Plumbing Code requires 3" up to tee on a washing machine.

 

[saf-t scissors]

It's NC. We're in the transition, so 2006 North Carolina and 2009 North Carolina (based on 2006 IPC) are both in effect.

2006 says horizontal branch of not less than 3" ID for a washing machine, so I guess that answers that question.

Thanks.

Edit: I guess the only other question I have is whether the washing machine should go at the end of the branch, or in the middle. The utility sink could go to either side of it. So long as I get a couple of feet between the wyes, does it matter? The kitchen sink will be 6-8 feet downstream of both.

 

[FloridaOrange]

Doesn't matter too much which order things are as they are all vented separately.
Or you could come up 3" to the WM tee, then 2" up to the laundry tub tee and go up with a 2" vent off of that. That would have one less wall assembly if your arrangement allows for that.
Just to be clear, with the FL code, you run the 3" to the tee, 2" vent and 2" trap for the washing machine.



Good luck with your remodel.