Ripping out several toilets to put in one shower, can I use the existing drain?

Hi Mallocup...

You can, IF the toilet vent connection is within 5 feet of the new shower PTRAP... ;)

Here, you would reduce the toilet drain from 3"-4" to 2" and install a 2" PTRAP at the shower. The toilet vent would need to be within 5 feet of the new PTRAP or you would need to run a new vent for the shower. The new vent would connect into the existing toilet vent above the floor and you should be all set here.

Questions? Let me know, OK?

Mark

Thank you sir, very much