Washing machine standpipe drain

[jodeci888]

Hello. Need some advice. Long story short, started smelling some foul odors and realized this! The drain is about 1 ft ABOVE the front load washing machine. It drains across to the right, not straight down.

Went to Home Depot today and picked up some couplings, PVC, a 90° elbow and a "U" piece of PVC. Wondering if I should just attach the 90° elbow to the U and add 18" of PVC OR add some PVC to lower the U and then add 18" of PVC.

Not sure what is best for this situation seeing as there is limited room and because of the height/direction the drain is running as well as the drain being ABOVE the washing machine.

Any advice would be greatly appreciated. Thank you.

 

[MicEd69]

You need to find out what the piping looks like behind the wall. If you smell sewer gas, then there apparently is not a P-trap there, or something has gone wrong inside the wall. You need a washing machine standpipe that meets the following criteria.

 

[jodeci888]

You need to find out what the piping looks like behind the wall. If you smell sewer gas, then there apparently is not a P-trap there, or something has gone wrong inside the wall. You need a washing machine standpipe that meets the following criteria.

Thanks for the reply. There is no p trap. The PVC is running slightly angled to the right into the main drain. I need to know where to put a p trap now on my side of the wall.

View attachment 41334

 

[Twowaxhack]

Open the wall behind the washer and let’s see the piping.

 

[jodeci888]

Open the wall behind the washer and let’s see the piping.

I'll upload a picture soon. Thanks for the reply.

 

[MicEd69]

The P-trap needs to be located relative to the floor and the main drain like the drawing I posted. If anything is entering the main drain above the point where you tie-in the washer P-trap, that P-trap will need to have a separate vent. I noticed the drawing I posted didn't have the size of the standpipe shown. Everything needs to be 2" from the standpipe to the main drain tie-in. If you need a separate vent for the P-trap, it can be a small as 1 1/4", but usually everyone runs 1 1/2" for separate P-trap vents. The drain line needs to be sloped 1/4" per foot from the P-trap to the main drain tie-in. The distance from the P-trap weir to tie-in point is limited by code and that distance is 5' if you are under the UPC, or 8' if you are under the IPC.

If you don't have access to tie-in a separate vent line to the vent stack or run a separate vent line through the roof, while I don't like them, an AAV (Air Admittance Valve) can be used if your local codes allow them.

 

[jodeci888]

The P-trap needs to be located relative to the floor and the main drain like the drawing I posted. If anything is entering the main drain above the point where you tie-in the washer P-trap, that P-trap will need to have a separate vent. I noticed the drawing I posted didn't have the size of the standpipe shown. Everything needs to be 2" from the standpipe to the main drain tie-in. If you need a separate vent for the P-trap, it can be a small as 1 1/4", but usually everyone runs 1 1/2" for separate P-trap vents. The drain line needs to be sloped 1/4" per foot from the P-trap to the main drain tie-in. The distance from the P-trap weir to tie-in point is limited by code and that distance is 5' if you are under the UPC, or 8' if you are under the IPC.

If you don't have access to tie-in a separate vent line to the vent stack or run a separate vent line through the roof, while I don't like them, an AAV (Air Admittance Valve) can be used if your local codes allow them.

Thanks for the info, sounds like I'm going to be rerunning the existing drain.

I'm going to have to get behind that wall and take a look I don't recall what it looks like but I know the area was extremely tight.

 

[jodeci888]

The P-trap needs to be located relative to the floor and the main drain like the drawing I posted. If anything is entering the main drain above the point where you tie-in the washer P-trap, that P-trap will need to have a separate vent. I noticed the drawing I posted didn't have the size of the standpipe shown. Everything needs to be 2" from the standpipe to the main drain tie-in. If you need a separate vent for the P-trap, it can be a small as 1 1/4", but usually everyone runs 1 1/2" for separate P-trap vents. The drain line needs to be sloped 1/4" per foot from the P-trap to the main drain tie-in. The distance from the P-trap weir to tie-in point is limited by code and that distance is 5' if you are under the UPC, or 8' if you are under the IPC.

If you don't have access to tie-in a separate vent line to the vent stack or run a separate vent line through the roof, while I don't like them, an AAV (Air Admittance Valve) can be used if your local codes allow them.

Murphy's law, my girlfriend's doing laundry so I was able to snap these two pictures. The long one is the washing machine drain and the second one with all the PVC is the one from behind my dryer which looks like it's all meeting up at.


Correct me if I'm wrong, but you're going to recommend that I put a new hole behind the washing machine and go straight across and add a new "T" to lower the whole section to match the picture you attached?

 

[jodeci888]

Open the wall behind the washer and let’s see the piping.

Murphy's law, my girlfriend's doing laundry so I was able to snap these two pictures. The long one is the washing machine drain and the second one with all the PVC is the one from behind my dryer which looks like it's all meeting up at.


Correct me if I'm wrong, but you're going to recommend that I put a new hole behind the washing machine and go straight across and add a new "T" to lower the whole section to match the picture that MicEd69 posted?

 

[MicEd69]

That is still a little confusing.

Is the washer drain line coming in through the left horizontal line of the picture of the 4-way fitting? If it is, does water sometimes flow/drip out of the open-air connection of the washer hose? Does that washer hose go all the way to the tee in that line?

Are there any fixtures draining in the vertical sewer line above the 4-way fitting? If not, it looks to me like that 4-way fitting was originally a collection of vent lines. Then someone decided to change out a 90 with a tee and use that for a cobbled-up washing machine drain.

So, IF all that is correct, yes, the way to fix this would be to add a 3x3x2 sanitary tee below that 4-way fitting such that the 2" inlet to that fitting is 6 to 18 inches above the floor. Then run a 2" line over to the washing machine area where you would install a 2" P-trap and a 18" to 30" high standpipe for the washer. If the weir of the P-trap is within 5 feet of the vertical drain line, you will not need a separate vent as you will be properly vented through the 3" vertical vent stack. The 2" drain line needs to be sloped 1/4" per foot towards the vertical stack.

 

[jodeci888]

That is still a little confusing.

Is the washer drain line coming in through the left horizontal line of the picture of the 4-way fitting? If it is, does water sometimes flow/drip out of the open-air connection of the washer hose? Does that washer hose go all the way to the tee in that line?

Are there any fixtures draining in the vertical sewer line above the 4-way fitting? If not, it looks to me like that 4-way fitting was originally a collection of vent lines. Then someone decided to change out a 90 with a tee and use that for a cobbled-up washing machine drain.

So, IF all that is correct, yes, the way to fix this would be to add a 3x3x2 sanitary tee below that 4-way fitting such that the 2" inlet to that fitting is 6 to 18 inches above the floor. Then run a 2" line over to the washing machine area where you would install a 2" P-trap and a 18" to 30" high standpipe for the washer. If the weir of the P-trap is within 5 feet of the vertical drain line, you will not need a separate vent as you will be properly vented through the 3" vertical vent stack. The 2" drain line needs to be sloped 1/4" per foot towards the vertical stack.

Yes, it's running across to the 4 way. The hose goes about 2 feet in. Never had a leaking problem (thank God). It's probably 8-10' away.

 

[MicEd69]

Yes, it's running across to the 4 way. The hose goes about 2 feet in. Never had a leaking problem (thank God). It's probably 8-10' away.

OK, then again, if there are no fixtures draining into the vertical line above that 4-way fitting, then it is a vent stack. And as such, you can drain the washing machine into it closer to the floor below the 4-way fitting. But if the washer standpipe is that far away, you will need to install a vent line within 5 feet of the P-trap. That vent line can be tied into that 1 1/2" line that is currently being used as the washer drain line.

Oh, the washer standpipe needs to meet the criteria in the drawings above, but it should also be 6" below the bottom of that new horizontal vent pipe going into the existing 4-way fitting.

 

[jodeci888]

OK, then again, if there are no fixtures draining into the vertical line above that 4-way fitting, then it is a vent stack. And as such, you can drain the washing machine into it closer to the floor below the 4-way fitting. But if the washer standpipe is that far away, you will need to install a vent line within 5 feet of the P-trap. That vent line can be tied into that 1 1/2" line that is currently being used as the washer drain line.

Oh, the washer standpipe needs to meet the criteria in the drawings above, but it should also be 6" below the bottom of that new horizontal vent pipe going into the existing 4-way fitting.

OK. Thanks for the information!

 

[jodeci888]

OK, then again, if there are no fixtures draining into the vertical line above that 4-way fitting, then it is a vent stack. And as such, you can drain the washing machine into it closer to the floor below the 4-way fitting. But if the washer standpipe is that far away, you will need to install a vent line within 5 feet of the P-trap. That vent line can be tied into that 1 1/2" line that is currently being used as the washer drain line.

Oh, the washer standpipe needs to meet the criteria in the drawings above, but it should also be 6" below the bottom of that new horizontal vent pipe going into the existing 4-way fitting.

OK. Can I add an AAV between the p trap and the end point?

 

[Twowaxhack]

I can already tell you that running that washing machine drain into those vents will be an illegal connection.

A washing machine is a high flow fixture/appliance. You can’t wet vent the fixtures below with a washing machine.

 

[MicEd69]

OK. Can I add an AAV between the p trap and the end point?

If they are allowed in your jurisdiction, yes, but why would you? If the new standpipe can be installed meeting the criteria in the above posts, the existing line that is illegally being used as a drain can be used as the vent line. An atmospheric vent is MUCH better.

 

[jodeci888]

If they are allowed in your jurisdiction, yes, but why would you? If the new standpipe can be installed meeting the criteria in the above posts, the existing line that is illegally being used as a drain can be used as the vent line. An atmospheric vent is MUCH better.

OK. Thanks for all the advice.

 

[jodeci888]

If they are allowed in your jurisdiction, yes, but why would you? If the new standpipe can be installed meeting the criteria in the above posts, the existing line that is illegally being used as a drain can be used as the vent line. An atmospheric vent is MUCH better.

Hello again. Finally gonna tackle this tomorrow. Wanted your advice regarding the 2 traps. Which do you recommend?

 

[MicEd69]

Mox Nix, it doesn't matter, or neither. The one just a drain/clean out that you use to drain the P-trap or perhaps cleanout any small debris. But if this is going to be outside the wall, I would go with a P-trap with a union like this.



Also, your picture shows 1 1/2" traps, but a washing machine standpipe needs to be 2". Yes, I know the existing pipe is 1 1/2" and it apparently has been working. But changing to the dimension required for a code standpipe MAY change that. Today's washing machines discharge water at a much higher rate than the older washing machines, and that is why the codes have changed for standpipe to be 2".

And if the standpipe is outside the wall, if you do have issues with any plugging, you can unscrew the union and have better access for snaking.

 

[jodeci888]

Mox Nix, it doesn't matter, or neither. The one just a drain/clean out that you use to drain the P-trap or perhaps cleanout any small debris. But if this is going to be outside the wall, I would go with a P-trap with a union like this.

View attachment 41442

Also, your picture shows 1 1/2" traps, but a washing machine standpipe needs to be 2". Yes, I know the existing pipe is 1 1/2" and it apparently has been working. But changing to the dimension required for a code standpipe MAY change that. Today's washing machines discharge water at a much higher rate than the older washing machines, and that is why the codes have changed for standpipe to be 2".

And if the standpipe is outside the wall, if you do have issues with any plugging, you can unscrew the union and have better access for snaking.

You beat me to the punch because I was literally about to ask you if should get one with a union!