Piping for washer drain

[Whatnot]

I started a thread a while back about this but it got a little off track I think it will be less confusing to just start over.
I just cut open the wall and took a picture of the pipes. Is it possible to put a washer drain in this wall? There is a door in the wall below so nothing can run on the right side of the bay with the 3" pipe.

 

[wwhitney]

The 3" pipe, you're confident that below the wall plate there is just a san-tee or combo with the toilet fixture drain coming in?

If so, I think you're in luck. A quick perusal of the Wisconsin Plumbing Code leads me to 382.31(13)(a) on vertical wet venting. It appears to allow a laundry standpipe to come into the 3" pipe, with the pipe between the standpipe san-tee and the toilet san-tee as a vertical wet vent.

So if that's correct (bears double checking, I've never looked at the Wisconsin Plumbing Code before), all you need to do is cut in a 3x2 san-tee into the 3" pipe, and then figure out where you're going to put the 2" trap and standpipe. Inside the wall looks very crowded, so maybe just exposed outside the wall?

BTW, the UPC would not allow that vertical wet vent, it restricts the fixtures other than the bottommost to be 2 DFUS or less, and for the UPC a washer standpipe is 3 DFUs. The IPC would allow the arrangement as a common vent "connected at different levels"; in their terminology a vertical wet vent is restricted to bathroom groups (which excludes laundry standpipes).

Cheers, Wayne

 

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[Whatnot]

The toilet on the other side of the wall tees into the 3" pipe between the floor joists. The bathtub drain tees into the 3" inside the downstairs wall below the toilet connection. From there the 3" goes all the way to the basement where it connects into the 4" main trunk.

 

[wwhitney]

Sounds good. Double check my reading of the Wisconsin Plumbing Code, then just cut in a 3"x2" san-tee at the desired height.

Cheers, Wayne

 

[Helper Dave]

Is that 3" at that point all vent? I guess I'm a little confused now based on your description from your last thread.

If there's nothing draining above there, and it doesn't look like there is if all the other vents are tying in there, then, no, you can't just tie into it and add a washer drain, sadly.

Sorry, Wayne, but you missed a couple things in WI code by just a hair. Lol

First, if there's a toilet draining on that 3" just at the floor there, it's a floor outlet fixture, not a wall outlet fixture. Most toilets in WI homes are floor outlets. So, 382.31 (13)(a)1. doesn't apply.

Floor outlet wet vent options are addressed in 382.31 (13)(c), and 1. limits the connecting fixtures to a dfu of 1 or less. Washers are 4 dfu in WI.

You'd have to tie in underneath there where the pipe is a drain, and then make sure to tie in a dry vent for the washer itself, as well.

 

[wwhitney]

Sorry, Wayne, but you missed a couple things in WI code by just a hair. Lol

First, if there's a toilet draining on that 3" just at the floor there, it's a floor outlet fixture, not a wall outlet fixture. Most toilets in WI homes are floor outlets. So, 382.31 (13)(a)1. doesn't apply.

Thanks for the correction. I was misled by 382.31(13)(a)1(e) which refers to water closets. I just couldn't believe that was there just for rear outlet WCs, so I figured they didn't really mean wall outlet fixtures, not having run into a plumbing code that makes that distinction. But I guess that's silly, they do mean wall outlet fixtures, and 1(e) is there just for rear outlet WCs.

Too bad that (13)(c) doesn't allow 2 DFU fixtures. Then a laundry tray could be put in.

It looks like 382.33(9)(c) would permit a laundry standpipe trap to be up to 10" below the floor level (26" - 36")? If so, the laundry standpipe could connect at the same level as the WC, if the san-tee can be replaced with a drainage pattern side inlet san-tee. The only upside for that somewhat unusual arrangement is that no additional venting would be required, it would be a 382.31(11)(a) common vent.

I agree that the WSPC doesn't provide any options for connecting a laundry standpipe drain to any of the labelled pipes in the wall. So you'd have to open up the floor, unless the lavatory drain happens to be reachable and is large enough to also carry the additional DFUs from a clothes washer (4 DFUs) or a laundry sink (2 DFUs).

Cheers, Wayne

 

[Whatnot]

Thanks for all the info. My main reason for starting this post was to find out if there would be any problem with the elevation of the existing vent pipes.
It would not be possible to get at the san-tee for the toilet without tearing up a lot of stuff.
It would be a lot easier to put a tee in the wall below the bathtub tee and run a pipe up. The sink it on the opposite wall and the joists are perpendicular so no way to get over there.

Is there any problem putting a bend in a vent pipe? It would clear up a lot of space if I could put an elbow on the toilet vent and shift it over to the next stud bay and then bring the washer drain up through that hole. Then probably cap the existing tee and put another up higher that connects both the toilet and washer vents.

 

[Helper Dave]

There's no problem bending a vent pipe. Stay with 45s, or lesser offsets on the vertical, and it's still considered vertical. That should keep most inspectors from giving you the stink-eye on a change like that.