Clothes Washer drain size

Users who are viewing this thread

DavidTu

Member
Messages
257
Reaction score
0
Points
16
Location
Seattle, WA
I apparently mistakenly sized my clothes washer drain based on dfu's, unaware of the special requirement in UPC calling for a 3" drain. I've seen discussion elsewhere saying that enforcement and interpretation of this vary widely inspector to inspector, region to region. I'm in Seattle WA and wondering how I will likely fare with the inspector.

Here is the setup: 2" trap & fixture arm going to 2" horzontal drain, which picks up a laundry sink and two lavs before going into a few feet of 3" pipe then 4" pipe on the horizontal and on down the stack.

Thanks in advance.
 

Gary Swart

In the Trades
Messages
8,101
Reaction score
84
Points
48
Location
Yakima, WA
From your description, you are just fine. You need a 2" standpipe for new washers which you have and then it increases in size and that too is just fine.
 

DavidTu

Member
Messages
257
Reaction score
0
Points
16
Location
Seattle, WA
From your description, you are just fine.

That's good to hear Gary... just to be clear, though, the horizontal 2" run (w/ 7 dfu) goes for about a total of 16' horizontal before going to 3" and 4" (horizontal for another 14' or so before vertical). Hope that doesn't change your reply.
 

Gary Swart

In the Trades
Messages
8,101
Reaction score
84
Points
48
Location
Yakima, WA
So long as you maintain the minimum slope of 1/4" per foot. That is required of every drain regardless of diameter of the pipe.
 

Inspektor Ludwig

Journeyman/Inspector
Messages
167
Reaction score
0
Points
0
Location
In the good ol' UPC
Are you wet venting this installation? Curious, what section of chapter 7 UPC are you referencing? I think I know which section you're talking about, the exceptions at the bottom of the DFU table. That language for 6 DFU is for laundrymats and multi-family laundry rooms where you would have a battery of clothes washers draining at the same time. It requires a 3" horizontal drain to address sudsing. Are there Inspectors that require a single family clothes washer to have a 3" drain on the horizontal? Must be Combo Inspectors because I've never heard of any Plumbing Inspector requiring that.
 
Last edited:
Top
Hey, wait a minute.

This is awkward, but...

It looks like you're using an ad blocker. We get it, but (1) terrylove.com can't live without ads, and (2) ad blockers can cause issues with videos and comments. If you'd like to support the site, please allow ads.

If any particular ad is your REASON for blocking ads, please let us know. We might be able to do something about it. Thanks.
I've Disabled AdBlock    No Thanks