Is an 1-1/2" lavatory drain running vertical to horizontal allowed over _ft? Or should it be 2" with a reducing san-tee? Thanks, Josh from CA

[Joshmee123]

Is an 1-1/2" lavatory drain running vertical to horizontal allowed over _ft? Or should it be 2" with a reducing san-tee for vent and stub out? Thanks, Josh from CA

 

[Breplum]

A single lav drain is one fixture unit. Calif PC/UPC says:
Vertical, Max. length is 65 ft.
Horiz max is "unlimited" as long as slope is maintained.

 

[Sponsor]

 

[Joshmee123]

A single lav drain is one fixture unit. Calif PC/UPC says:
Vertical, Max. length is 65 ft.
Horiz max is "unlimited" as long as slope is maintained.

So in the wall and under slab tying into 3"main should be fine on 1-1/2"?

 

[John Gayewski]

So in the wall and under slab tying into 3"main should be fine on 1-1/2"?

Yes it should be fine. Most people just run 2"because snaking is more difficult inside of 1.5" and people like to over size things not really sure why other than making changes later can be easier if your over sized. Also it's easier to account for a whole project's worth of fittings if everything is 2".

 

[Jeff H Young]

I usually run 2 inch but remodel work or tighter spaces nothing wrong with 1 1/2 holes in framing , coming up out of concrete and sweeping into walls especially when concrete footing is there and you don't have all the concrete blown out.
So as much as I prefer 2 inch Its ok to go 1 1/2 " just a lav but if its easy enough I stick with 2

 

[Joshmee123]

Thanks guys, I'm going to grab an ABS fitting saver and drill it out to 2 inch. That way it doesn't back up and I have piece of mind. Appreciate the help as usual brothers!