Layout Help With Basement Bathroom Rough-In

[harry_homeowner]

Hi everyone. I'm from Minnesota. I'm building a new bathroom in the basement (contains vanity sink, shower, toilet). Pulled city permits myself. I just failed Rough-In inspection #3... The inspector's reasons were:

1. I put the Backwater valve on the Main 4" Line, I need to make sure the Backwater valve services only the new basement bathroom fixtures
   
   
2. Shower vent was wrong (horizontally running below flood-rim)
   
   
3. Toilet vent was wrong (not on the downhill side of the toilet)

Before I call up the inspector again, I wanted to make sure I had my new design right... (easier to follow if you read the pic from Right-to-Left).

Things that I'm particularly unsure of legality-wise is:
- Whether I can put the Toilet Vent right next to the Backwater Valve
- Whether the 3" to 4" Closet Flange can be directly connected to a horizontal Long Sweep 90

Any help at all would be appreciated! Thank you!

 

[Terry]

Do they allow wet venting where you are at?
Normally a lav run with 2" for the wet portion and then vented with 1.5" above the trap arm for the lav would also handle the shower.
If not, then yes the vent for the shower would be vertical until it's above the flood rim. We normally do our reventing at 42" above the floor, covers the sink heights too.
I don't see a problem with venting the toilet upstream of the backwater valve.

 

[Sponsor]

 

[harry_homeowner]

Do they allow wet venting where you are at?
Normally a lav run with 2" for the wet portion and then vented with 1.5" above the trap arm for the lav would also handle the shower.
If not, then yes the vent for the shower would be vertical until it's above the flood rim. We normally do our reventing at 42" above the floor, covers the sink heights too.
I don't see a problem with venting the toilet upstream of the backwater valve.

Hi Terry,

Appreciate the response. Think it gave me the knock on my head I needed...

For Wet venting, I found this Minnesota specific diagram which seems to spell specific guidelines for the state.

I feel pretty dumb... I think I get the standard way to do it now. If I understand correctly, I could've 2" wet vented from the Lav, and then did my 2" drain runs to the Shower and Toilet. In order of depth, the Lav would be the highest fixture, the Shower would drain downstream of the Lav, then the Toilet would drain downstream of the Shower, making it the lowest downstream fixture.

The layout in my original post is part of a design where I vent every individual fixture vertically with its own dedicated vent... I guess that's overkill, but I assume there won't be anything functionally wrong with the system if I vertically vent each fixture right? Unless...

Again, truly appreciate the response. I didn't even know what a vent was when I started this project... probably not the greatest starting point.

 

[wwhitney]

You can try to dry vent each fixture individually, but those individual vents have to meet all the vent rules.

So the dry vent has to come off the fixture trap arm before it joins any other drains (which is not true for the WC vent in your OP), and the vent has to come off vertically and rise (at least 45 degrees above horizontal) until 6" above the fixture flood rim (which is not true for your shower).

With horizontal wet venting, you can delete those two dry vents. The lav gets a 2" vent and 2" drain, and the shower trap arm joins the lav horizontally, within 60" of the shower trap (the trap arm length limit for a 2" trap) and within 2" vertically (maximum fall, the trap weir rule). And then the combined drain joins the WC drain (which has to be last for UPC horizontal wet venting), and that junction has to be within 6' of pipe length from the closet flange (the length limit for a WC; the trap weir rule does not apply, as the WC has an integral trap that is refilled after each flush).

Cheers, Wayne

 

[Jeff H Young]

harry homeowner, I don't see where your Minnesota code in what you posted shows a vent downstream of the water closet? is he contradicting that? your correction appears to have a downstream vent and a proper horizontal wet vent which has you covered but not so sure its needed there.