Back to back toilets in basement

[Andy2019]

Hi folks

We are planning to develop our basement this summer to add two bathrooms back to back with a shower stall, a toilet and a sink in each bathroom. I grabbed a few fittings yesterday at Home Depot to see how I would connect two toilets and this is what I come up with - see the attached picture. The double wye will be horizontal under the slab, the toilets will be farther away from each other than they are at the picture right now. I just connected everything as-is for the demonstration purposes. Will this work in my situation? I haven't thought about the rest of the fixtures and their connections at this point. Will appreciate any advice.

Cheers!

 

[Sylvan]

Looks good BUT what about the venting

 

[Sponsor]

 

[Andy2019]

Looks good BUT what about the venting

I haven't planned the venting yet. My thinking was to have a 3 " sanitary tee above the double wye on the picture to have a vertical vent going to the attic.

 

[hj]

There is a good chance that when you flush either toilet, it will affect the water in the other one due to the venturi effect caused by the water flowing past the other's connection point. A vent before, or after, the double Y will NOT prevent the problem.

 

[Andy2019]

There is a good chance that when you flush either toilet, it will affect the water in the other one due to the venturi effect caused by the water flowing past the other's connection point. A vent before, or after, the double Y will NOT prevent the problem.

Thanks for the feedback!
Is there a way to avoid this problem? I am in the planning phase right now, so I can move toilets to their optimal position. What would you suggest?

 

[Cacher_Chick]

The toilets can be back to back, but that does not mean the wyes in the building drain need to be.

 

[Terry]

What else is there? This drawing is pretty basic and the 90 bends should have been drain with 45's in many cases.

 

[hj]

How deep is the sewer line?

 

[Andy2019]

What else is there? This drawing is pretty basic and the 90 bends should have been drain with 45's in many cases.

Instead of the bathtubs I am planning to have two shower stalls, then two toilets and two sinks at the end.

I was also wondering how the plumbing diagram would change if I wanted to add washer/dryer in one of the bathrooms?

 

[Andy2019]

How deep is the sewer line?

Unfortunately, I don't know; we haven't touched the slab yet.

 

[Cacher_Chick]

Instead of the bathtubs I am planning to have two shower stalls, then two toilets and two sinks at the end.

I was also wondering how the plumbing diagram would change if I wanted to add washer/dryer in one of the bathrooms?

The laundry should be ran separately and tied in downstream of the bath group.

 

[Terry]

The laundry should be ran separately and tied in downstream of the bath group.

The laundry is downstream from any bathroom group that is using wet venting. The washer will suck traps dry.

You can vent every fixture. That is also an option.