: I am adding a new 2" drain to an existing 4" toilet drain in my basement floor. I plan on cutting in a 4x2 wye fitting and then piping to the new shower location about 5' away.Is this correct and do I need to vent the new 2" drain? Thanks for any advice.

Reply:
That will work and yes, you do need to vent the shower trap. The vent fitting can be a 2" X 1-1/2" TY coming off the drain pipe not less than a 45 degree angle.
Good Luck & Happy Holidays. e-plumber