Washing Machine P Trap Has No Vent

[Phant82]

Hello! I am not a plumber and will always hire a professional for repairs. However, I am curious as a home owner to know how big or small of a problem I have on my hands. I live in a single story brick ranch built in 1959. I bought the home late last year. See the picture I uploaded: this is the beginning of the sewer drain line in my home, in the crawl space. It starts on the far end of the home with the washing machine. There is a standpipe leading down to this p trap in the picture, and notice the p trap is not vented, and it connects directly into the main sewer line. The sewer line then continues on under the kitchen sink (the p trap and vent for kitchen sink is not in the crawl, it is further up in the home), then under the guest bathroom, then it cuts a 90 degree angle and continues under the master bathroom before exiting the home to the street. When my washing machine drains, I usually get a waft of rotten egg smell coming up through the washing machine standpipe. I imagine this is the sewer gas needing a place to escape since the p trap is not vented. When I run my kitchen sink or guest bathroom sink, I can hear "glug glug glug" coming from my washing machine standpipe. Again, I'm guessing the air needs a place to go. I would welcome any insight to help me understand the level of the issue I am dealing with. Is this something that can get worse, or can I leave it alone for now and deal with the occasional gurgling and rotten egg smell? Is there any chance the washing machine p trap would use the kitchen sink vent for venting? They are probably 20 feet apart so I would guess not. Is there a way to cut the drain line and install an air admittance valve after the p trap? We have these in our home but not directly in line with our sewer line. Thanks for any help.

 

[Terry]

The P-Trap for the washer needs to be on the same floor, not in the crawl space.
Remove the trap there and replace with a long turn 90, then add a p-trap behind the washer. You can vent with an AAV.

This one is vented through the roof, but you could also use an Auto Air Vent.

804.1 All plumbing fixtures or other receptors
receiving the discharge of indirect waste pipes shall be
approved for the use proposed and shall be of such
shape and capacity as to prevent splashing or flooding
and shall be located where they are readily accessible
for inspection and cleaning. No standpipe receptor for
any clothes washer shall extend more than thirty (30)
inches (762 mm), nor less than eighteen (18) inches
(457 mm) above its trap. No trap for any clothes
washer standpipe receptor shall be installed below the
floor, but shall be roughed in not less than six (6)
inches (152 mm) and not more than eighteen (18)
inches (457 mm) above the floor.

 

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[Chefwong]

Just a weekend warrior...

Is this a code thing ? Or that and not common practice. Meaning if he just a AAV in the crawlspace ?

 

[Terry]

Just a weekend warrior...

Is this a code thing ? Or that and not common practice. Meaning if he just a AAV in the crawlspace ?

If the standpipe is too tall, it siphons anyway. I would not count on a vent in the crawl doing anything helpful.

 

[Themp]

Terry, on your picture example, it shows a hose bib on the vent pipe. What would that be used for? Thanks....

 

[FullySprinklered]

Terry, on your picture example, it shows a hose bib on the vent pipe. What would that be used for? Thanks....

Yeah, Terry, 'splain me that.

 

[Terry]

New construction there, it's a cleanout, which is required, and then there is a sillcock threaded in that allows filling the waste and vents from one of the washer valves with a washing machine hose, which has two female threads for the connection.
After the plumbing test on the waste and vents is passed off, the sillcock is removed and a cleanout plug is installed.

 

[FullySprinklered]

Thanks. If my granddaughter ever decides to marry a plumbing inspector, I ain't showing up for the wedding.

 

[nholt]

I found this thread while googling. In the picture posted by Terry, are those 2x4s that the pipe is going through? I thought you could only drill through a certain percentage of a 2x4 without compromising its structurally. Or is that not a load bearing wall? I have a similar situation like the one in the photo, a window and a bunch of 2x4s. I think I might just extend /fur out the wall out a few inches rather than drill through my load bearing frame to run my horizontal drain over to my washing machine.

 

[Jadziedzic]

Those look to be 2x6s in Terry's picture. You can use "stud shoes" to reinforce load-bearing studs if you're concerned about the reduction in load-carrying capacity.