Can I come of my shower drain with a 90 and run 30" pipe to the trap and then down my stack? No room for a trap under shower.

Hi Bobhar...

Not only are you not supposed to do what you propose, but you also seem to be forgetting about the vent needed for the new shower... ;) Or, at least you didn't mention the vent.

You may be able to run an INDIRECT drain from the shower over to a properly vented PTRAP... ;) But first, tell me why you can't install a PTRAP under the shower, please? Is it that there is concrete in the way? If so, you just need to chip out a small hole in the floor so the trap rests in it (on sandy bed)...

Back to you...

Mark

Can I come of my shower drain with a 90 and run 30" pipe to the trap and then down my stack?
Good catch, Mark! In addition he would be installing a running trap,(see image) and inspectors frown on those. Regards, Tom