Rough-In plumbing/venting help

[Corey_Honadel]

So, I recently submitted my rough-in inspector to my local inspector and did not pass. The reason for my failure is "need to vent fixtures properly". I've asked my inspector to elaborate on what is incorrect about the venting and have not been able to get a response other than "I cannot design for you so I cannot tell you how or what it is you would need to do to correct.". It's really discouraging to get zero help or even an explanation as too what is wrong, so I am hoping to get some feedback on here.

Does anyone have some advice from initially looking as what could be wrong with my venting?

Here is what I have...... I am adding in a bathroom to my basement (straddling my main drain) with a small closet on the side of it. The bathroom will consist of a tub, toilet, and a dual vanity. The closet will have my water softener with a drain for the regen and another 2" drain coming up that'll be capped off. My plans in the future are to relocate the kitchen above this space so I wanted to have the drain ready for it. The fixtures I was assuming would all vent via the vanities 2" as a wet vent system. The one thing I thought could be wrong was the 2" to the vanity not being 3", I asked the inspector about it and he said it wouldn't. Also note, this was a storage room so the wall locations are NOT where they will be. I'm just keeping them up to keep dust/dirt away from the living spaces.

I am also in Wisconsin.

 

[Corey_Honadel]

Also want to say I love the forum and have to using it as a resource for a while now. Just never had anything helpful for anyone that wasn't already addressed or anything of my own worth posting until now

 

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[Reach4]

Because the softener standpipe enters the flow, it means that the lavatory cannot wet vent the shower or toilet. Oh, wait. There is another big problem. There is other drainage coming from right to left. That would also interrupt the attempt to wet vent the bathroom with the lavatory. Sorry I don't have a good solution for you.

If you could route the softener drain to be downstream of the bathroom stuff, and presuming that softener standpipe is vented, I suspect you would be OK.

Softener drains before the standpipe are pressurized, so you could probably go up and over to dump into the new softener.
I don't know what that pipe with the red thing is. If it is a vent pipe, it will not help. Or maybe you could run the softener standpipe drain alongside and join downstream of all of the bathroom stuff.

I am not a pro, and I don't know WI plumbing code. But from what I have seen, that code doesn't look odd. So if what you do would satisfy both IPC and UPC, I would guess it would be OK in WI.

But what you have does not satisfy UPC or IPC. For wet venting, the drain pipe from the lavatory would be 2 inch.

There may be problems that I did not spot.

 

[Corey_Honadel]

Hey. Thanks for the reply. The red 2" capped part is a long sweet drain that will end up in the future being a drain for a kitchen above.

Thinking along those lines, could I theoretically add a vent on the pipe that is feeding my softener drain?

 

[Corey_Honadel]

Here is a crude drawing.

 

[wwhitney]

I would have to check the Wisconsin code to see if there's anything unusual about it, but here are my comments based on the UPC/IPC:

- I believe that only fixtures below the downstream sewer manhole elevation (or something like that) are supposed to be behind the backwater valve. So typically that means only basement fixtures, not any fixtures from the story above. If the future kitchen drain is for a kitchen above the basement, it should join the building drain downstream of the backwater valve.

- Likewise if there are any fixtures from above the basement that enter the building drain upstream of the area where you are working on the building drain, that's a problem with your backwater valve location.

- Plus as Reach4 noted, to wet vent the WC, you need to keep the bathroom group separate from other fixtures.

- In the basement, you are going to need a dry vent for the lav and a dry vent for the softener standpipe. But you should be able to use the lav to wet vent the tub and WC.

- To do all that, I suggest that you establish a new horizontal branch drain above your building drain. At the upper end it would consist of the 2" double lav drain joining the (1-1/2" or 2") tub trap arm, to wet vent the tub. Then it would continue as 2" to join the WC drain, to wet vent the WC. Then the dry vented softener standpipe drain would join in, after all the wet venting. Then the backwater valve. And then the new branch can join the existing building drain, e.g. with a wye and a 45.

- If for some reason the upstream fixtures on the building drain are all other basement fixtures, then you would instead join the new bathroom branch to the building drain before the backwater valve, so the backwater valve protects all the upstream fixtures. If there's a mix upstream, then you'd need a second backwater valve for those basement fixtures.

- Oh, and the sizes above are minimums, it may be prudent to run the 3" on the new branch farther upstream to allow for a 3" cleanout. Although with the backwater valve, you'd want to be sure that any cleanout is really water tight, or else above the lowest fixture flood rim behind the backwater valve.

Cheers, Wayne

 

[John Gayewski]

It looks like the toilet would be properly vented if you cut in a different drain for the future kitchen. Then just cut that branch from the wye for the shower off right at the joint and use a ram bit. Instead of having the shower trap come off of the wye, run out straight into the imaginary wall with a 90 looking up. Then sanitary tee for the trap and vent up in the wall. You should be good and minimal change.

 

[Corey_Honadel]

Thanks wwhitney and John.

I'll ask the inspector about the backwater valve specifically and see if I get something useful. Main reason I added that is because a couple years ago, many houses a couple blocks from me have a lot of damage from some sewage backup and I want to prevent that while I'm in the ground. My house is located in a valley within the city if that matters.

- To do all that, I suggest that you establish a new horizontal branch drain above your building drain. At the upper end it would consist of the 2" double lav drain joining the (1-1/2" or 2") tub trap arm, to wet vent the tub. Then it would continue as 2" to join the WC drain, to wet vent the WC. Then the dry vented softener standpipe drain would join in, after all the wet venting. Then the backwater valve. And then the new branch can join the existing building drain, e.g. with a wye and a 45.

I'll have to draw this out to envision it but I picture the entire bathroom drainage all one assembly dumping down into a 4x4x3 to the main drain, ya? Can all this be alleviated by dry venting the toilet and the softener?

 

[wwhitney]

What fixtures if any are connected upstream of the building drain that you exposed, and what floors are they on? Are there any other basement fixtures?

Cheers, Wayne

 

[Corey_Honadel]

What fixtures if any are connected upstream of the building drain that you exposed, and what floors are they on? Are there any other basement fixtures?

Cheers, Wayne

The entire upper floor as well as the basement. The backwater valve right now is the last thing in my entire build drain.

 

[wwhitney]

What other fixtures are in the basement?

Cheers, Wayne

 

[Corey_Honadel]

What other fixtures are in the basement?

Cheers, Wayne

Washing machine, utility sink, and an emergency floor drain.

 

[wwhitney]

OK, first, on the backwater valve. I looked a bit at the WI plumbing code (SPS 382) and noticed SPS 382.30(11)(2) specifies backwater protection when the building drain is subject to backwater, but doesn't have any stipulations on what floors are served by the drains protected by the backwater valve. In which case if I haven't missed anything, you can put the backwater valve on the entire building drain, as you have done.

But let me just point out what will happen with and without the backwater valve given that all basement and upstairs fixtures are behind it. Without it, if the sewer gets backed up, other people's sewage could flow back up your building drain, and flow out the fixture with the lowest flood rim, which would be the emergency floor drain. And that could be a lot of sewage.

With it, if the sewer backed up, the backwater valve is supposed to close, keeping other people's sewage out of your house. But if you are unaware that this has occurred, and you continue using the fixtures (upstairs or downstairs), then your sewage will back up behind the valve and come out of the emergency floor drain. Which would presumably be less sewage.

The idea behind putting all the basement fixtures behind the backwater valve, and only the basement fixtures, is that only the basement fixtures could cause a backup inside the house when the backwater valve is closed (on the assumption that the sewer overflow outside is below your first floor, so the backup on the public side of the backwater valve could not reach your first floor). If all those basement fixtures are in the same room, then presumably you'd notice the backup and stop using those fixtures. If you have basement fixtures in multiple rooms, sounds like that might not help, as you might not notice the emergency floor drain backing up.

Anyway, given all that, and given that it sounds like it would be hard to separate all the basement fixtures so that only they are behind a backwater valve, and assuming I've found all the relevant parts of SPS 382, then you can decide to either leave the backwater valve as is, or get rid of it. I won't worry about the backwater valve any further.

Next I'll comment on the bathroom group venting.

Cheers, Wayne

 

[wwhitney]

I'll have to draw this out to envision it but I picture the entire bathroom drainage all one assembly dumping down into a 4x4x3 to the main drain, ya?

Yes, in what I wrote in my first post, all the bathroom fixtures would come together in a 3" horizontal branch above the 4" building drain, and it would dump into the building drain with a 45 into a 4x4x3 wye. The softener could join the bathroom group 3" branch after all the bathroom fixtures, or it could directly join the 4" building drain.

Can all this be alleviated by dry venting the toilet and the softener?

The softener standpipe needs a dry vent regardless. Right now the shower is not correctly wet vented, as the softener can't join the wet vent, it needs to join downstream.

Thus if you redo do the lav/softener/shower nexus, so that the lav and shower join first, and then the softener joins in, and the shower trap arm complies with the length limits and falls no more than one pipe diameter before joining the lav, and you dry vent the WC, then everything will be properly vented. The lav, softener, and WC would be dry vented, and the lav would be wet venting the shower.

BTW, if your inspector literally said nothing beyond "need to vent fixtures properly" then they are being obstructionist. At a minimum the correction notice should say "shower and WC not properly wet vented."

Cheers, Wayne

 

[Corey_Honadel]

Thus if you redo do the lav/softener/shower nexus, so that the lav and shower join first, and then the softener joins in, and the shower trap arm complies with the length limits and falls no more than one pipe diameter before joining the lav, and you dry vent the WC, then everything will be properly vented. The lav, softener, and WC would be dry vented, and the lav would be wet venting the shower.

Perfect, I like this approach the best. For the WC I can add in a 4x4x1.5 sanitary tee on the vertical part of it right? I assume so but I now find myself questioning everything.

BTW, if your inspector literally said nothing beyond "need to vent fixtures properly" then they are being obstructionist. At a minimum the correction notice should say "shower and WC not properly wet vented."

It is really unfortunate, two contractor friends of mine (they don't know plumbing) said this guy was actually pretty condescending towards DIYers. I pulled a permit and everything to 1) ensure my work is correct and 2) following the rules on what you should do. So many people I know do work all the time without permits or purchase property where work is done incorrectly and just causes a headache later. I just wanted to be sure it was correct.


This was from the inspection notes:

Permit Type: Plumbing
Permit number: 20220184
Site address: -------------
Inspection: Plumbing Rough In
Status: Not Approved
Comment:need to vent fixtures properly.

And yes quoting him when I asked about my 2" wet vent and what was wrong exactly, I got this response:

"Hi Corey- no that is only if done correctly. I cannot design for you so I cannot tell you how or what it is you would need to do to correct."

 

[wwhitney]

Perfect, I like this approach the best. For the WC I can add in a 4x4x1.5 sanitary tee on the vertical part of it right? I assume so but I now find myself questioning everything.

No, a dry vent has to come off vertically (at least 45 degrees above level) and rise vertically until 6" above the flood rim. So no horizontal dry vents under the slab. You can come off with 4x4x1.5 (?) wye if you can get that to work. [Not sure if WI has an exception for when "structural conditions" preclude the vertical rise, but with the advent of wet venting, I think such exceptions are less commonly allowed even when in the code.]

You'll have to figure out if the reconfiguration of the lav/shower/softener nexus and adding the WC dry vent is more or less work than just redoing the whole branch at a higher elevation, as I originally suggested. If it's the same, I'd recommend my first suggestion, as it's cleaner and has one less dry vent to deal with.

Cheers, Wayne

 

[Jeff H Young]

No, a dry vent has to come off vertically (at least 45 degrees above level) and rise vertically until 6" above the flood rim. So no horizontal dry vents under the slab. You can come off with 4x4x1.5 (?) wye if you can get that to work. [Not sure if WI has an exception for when "structural conditions" preclude the vertical rise, but with the advent of wet venting, I think such exceptions are less commonly allowed even when in the code.]

You'll have to figure out if the reconfiguration of the lav/shower/softener nexus and adding the WC dry vent is more or less work than just redoing the whole branch at a higher elevation, as I originally suggested. If it's the same, I'd recommend my first suggestion, as it's cleaner and has one less dry vent to deal with.

Cheers, Wayne

WI code looks like neither IPC or UPC.
Corey that's a tough one on inspector its not his job to tell you how to do it. But I think its his job to tell you which code you violated. He might not be able to tell you physically how to make it all work.
Corey As far as backwater valve I'm giving you a scenario, stoppage outside of house backs up closing B/W valve. mean while upstairs you are using your plumbing where does all the poo Go? downstairs in basement.
Now without upstairs line NOT on BW valve if Valve closes and you keep using upstairs it will begin to back up but won't flood basement

 

[Reach4]

It is possible the inspector would have been more forthcoming if there had only been one or two things not vented properly; maybe not... But there was no simple answer for your case.

 

[wwhitney]

It is possible the inspector would have been more forthcoming if there had only been one or two things not vented properly;

There were only two things not properly vented in terms of the under slab plumbing: the shower (since the softener came in at the wrong place) and the WC. The lav and softener venting will be above slab, so their venting won't be reflected under slab.

Cheers, Wayne

 

[Reach4]

Yes, if the softener was vented properly above the floor.

Attached sketch is probably representative of prior suggestions. Blue circles are vents. It is more conceptual, and things would be adjusted to better match the existing trenching and use available fittings.