WC directly over horizontal drain and wet vent

[benjdwilson]

Thanks for the great site - this is my first post but I have learned so much from you guys.

I have a basement remodel in which I'd like to tie into an existing 3" horizontal underslab drain line for a bathroom. The existing drain line is directly beneath where the WC will be installed. My question: can I tie into the drain directly from above with a long-sweep wye for the WC? Upstream of the WC the line will turn vertical for the vent as well as for where the shower, lav, and a floor drain will tie in.

I don't think this is any different from the way a WC is often wet vented, but I don't think i've ever seen an example where the WC drain comes in from above, only from the side.

Attached are a couple of drawings of the plan. Thanks for your help!

 

[Terry]

As long as you have a long sweep into the 3".