P-trap in washing machine drain?

Reply

  #1  
Old 05-30-15, 07:36 AM
J
Member
Thread Starter
Join Date: May 2012
Posts: 49
Received 0 Votes on 0 Posts
P-trap in washing machine drain?

I had a contractor doing some work at my house relocating our laundry room to what was a large closet. I had to dismiss him when I found out he wasn't paying his workers so there's some unfinished work.

Today, I'm going to be connecting the washing machine drain to the sewer line. It looks like he put a sanitary tee on the soil pipe of a nearby toilet for this purpose. My question is, should I put a p-trap under the washing machine drain before running the sloped pipe over to the tee? Also, is the gap around where the drain hose fits into the stand pipe in the laundry room an adequate vent?

My house is pier-and-beam so I want to be sure there isn't some sort of p-trap or other piping configuration underground that should make the p-trap a no-go. The drain pipe from the old washing machine location doesn't seem to have had a p-trap under the house, unless it's under ground.
 
  #2  
Old 05-30-15, 07:51 AM
chandler's Avatar
Banned. Rule And/Or Policy Violation
Join Date: Dec 2005
Location: USA
Posts: 39,965
Received 6 Votes on 6 Posts
The washing machine drain must have a ptrap. Where it is in your situation, only you can find out. You don't want two traps. If he is tying into another drain, then an underground trap would not be present in most cases. Our plumbing pros will be along to address the soil stack installation, but he'll need to know how far away from he washing machine the stack is.
 
  #3  
Old 05-30-15, 08:10 AM
F
Member
Join Date: Mar 2006
Location: Wet side of Washington state.
Posts: 18,495
Received 36 Votes on 28 Posts
Washing machine drain piping needs to be 2 inch nominal size pipe and it absolutely needs a trap. I am not a plumber but as I understand things this trap may not be underneath the floor.

The sanitary tee in the piping from the toilet sounds fishy to me. Can you post a picture?

ALL traps need to be vented on the outlet side. The drain standpipe does not serve as any kind of vent.
 
  #4  
Old 05-30-15, 08:49 AM
J
Member
Thread Starter
Join Date: May 2012
Posts: 49
Received 0 Votes on 0 Posts
I just looked and there is not a p-trap in the wall (which is already finished out)...just a straight standpipe to under the house.

The soil pipe is about 15 ft away and I've only got 2-3" of available drop over that length due to the joists.

Also, when you say all traps must be vented on the outlet side, does a having a common vent on another sewer line (such as the soil pipe) suffice?
 
  #5  
Old 05-30-15, 09:15 AM
F
Member
Join Date: Mar 2006
Location: Wet side of Washington state.
Posts: 18,495
Received 36 Votes on 28 Posts
Also, when you say all traps must be vented on the outlet side, does a having a common vent on another sewer line (such as the soil pipe) suffice?
Depends on the configuration but I can assure you that fifteen feet is WAY too far for venting a 2-inch trap.

Here is a page of Google images for laundry drain installations. Unless your installation closely parallels one of these it is absolutely wrong. Did your former contractor get a permit from the local building authority for this work?

https://www.google.com/search?q=laun...w=1152&bih=711
 
  #6  
Old 05-30-15, 09:37 AM
J
Member
Thread Starter
Join Date: May 2012
Posts: 49
Received 0 Votes on 0 Posts
No, from what I can tell there is no trap in the wall behind the washer and putting it under the house would make it more than 30" below the top of the standpipe. I can see straight through to the ground under the house through the standpipe. The contractor no longer replies to my inquiries since I fired him.

Out of curiosity, what is it about island sinks that makes it OK to put the trap under the house but it can't be done with washing machines?
 
  #7  
Old 05-30-15, 09:49 AM
F
Member
Join Date: Mar 2006
Location: Wet side of Washington state.
Posts: 18,495
Received 36 Votes on 28 Posts
I don't think that island sink traps are allowed beneath the floor either. I think the ONLY traps that are allowed below floors are for bathtubs and showers.

Maybe our resident plumber, Mike Lawrosa, has a better answer for you. Hopefully he will check in later today or maybe tomorrow.
 
  #8  
Old 05-30-15, 09:59 AM
J
Member
Thread Starter
Join Date: May 2012
Posts: 49
Received 0 Votes on 0 Posts
That's interesting...I've seen two types of drains for island sinks: a trap under the house and the trap in the cabinet with an "air gap" configuration between the trap and the vent (in a nearby wall).

My dad was a master plumber and didn't seem surprised by our island sink having a trap under the house. He's been out of practice a while though...which is why I came here with the washing machine question.
 
  #9  
Old 05-30-15, 10:12 AM
F
Member
Join Date: Mar 2006
Location: Wet side of Washington state.
Posts: 18,495
Received 36 Votes on 28 Posts
As I stated in my first response I am not a plumber; I AM somewhat familiar with the UPC, the Uniform Plumbing Code (Uniform Plumbing Code - Wikipedia, the free encyclopedia) BUT the UPC is a "model code" and has no power of enforcement until enacted into law by a legislative body. This legislative body has the power to add to or delete from the model code as they see fit. Also, the legislative body may be at the state, county (parish) or municipal level, sometimes all three. The end result is that ONLY the LOCAL code must be followed and it is possible in your area that the prohibitions of underfloor traps in the model code were removed in the enabling legislation.

End result, while your installations do not meet the letter of the model code they MAY (or may not) be legal in your jurisdiction.

That's all I have, good luck on your project.
 
  #10  
Old 05-30-15, 01:06 PM
Handyone's Avatar
Member
Join Date: Aug 2000
Location: U.S.
Posts: 5,450
Received 0 Votes on 0 Posts
At this point, it doesn't matter if trap is allowed below floor or not. It could be in some areas, but that would make the standpipe height more than 30" above trap, this cannot be per the UPC

We like to help here, but you might want to check with local building department.
- Is trap allowed in crawlspace? Could be per local code
- Is 30" the max standpipe height? Some allow 48"

Your dad might have approved the island sink trap under house because the drop was less than 24"
 
  #11  
Old 06-01-15, 06:11 AM
M
Member
Join Date: Dec 2003
Location: USA
Posts: 994
Received 0 Votes on 0 Posts
Well, either my inspector was seriously lazy or the IPC is a lot different from the UPC (I've heard that it is, but am not a pro). My washer standpipe is 36" and the trap's in the crawl space.
 
  #12  
Old 06-01-15, 03:08 PM
F
Member
Join Date: Mar 2006
Location: Wet side of Washington state.
Posts: 18,495
Received 36 Votes on 28 Posts
Well, either my inspector was seriously lazy...
While I am sorry to say it, that IS a distinct possibility.

It was almost forty years ago that I installed a new electrical service in my house. One thing the "inspector" dinged me on was that he couldn't see the connection of my grounding electrode conductor to the incoming water pipe. The code is adamant that this connection needs to be within five feet of the pipe entering the house and it was. Problem was, this guy was about three hundred pounds and he didn't want to crawl thirty feet from my crawl space entrance to where the pipe entered the area.

Amazingly, this guy's first inspection was made from the comfort of his automobile driving past my house. Since he had not signed the permit (although he did call the utility stating it was fine) I called him back. I ended up having three inspections and he never did sign the permit. And no, I never changed that grounding connection either.
 
  #13  
Old 06-01-15, 03:32 PM
chandler's Avatar
Banned. Rule And/Or Policy Violation
Join Date: Dec 2005
Location: USA
Posts: 39,965
Received 6 Votes on 6 Posts
That's odd. Our inspector doesn't sign inspections either. I told him I would remove it from the clear protection sheet for him, and he said not to bother. He OK's everything from his phone to the office. This is small town USA, so it really surprises me.
 
  #14  
Old 06-05-15, 10:07 PM
J
Member
Thread Starter
Join Date: May 2012
Posts: 49
Received 0 Votes on 0 Posts
Thanks for all the replies and sorry for my absence. I called the guy who did the inspection on the house when we bought it and also talked with my dad. They both gave me the impression that since it will be in the crawl space where it can be accessed and serviced if necessary (as opposed to in/under a slab) it isn't to the letter of the UPC but would pass inspection. So I took that route and put an in-line vent after the p-trap and drained to the soil stack (about 2" drop over 15'). No issues so far.

If it gets problematic or becomes a sticking point on a future inspection, I'll just do the code work then.

Thanks again!
 
 

Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description:
Your question will be posted in: