: I am installing a bathroom (toilet, vanity, shower stall) in my basement. There is a sewage ejector pump down there already. Can I just cut into the existing basin? also since the basin has a vent stack, do I still need to vent the fixtures ?

John,
Plumbing fixtures run to a sewage ejector still needs to be treated as normal plumbing with vents.
That being said, it is okay to tie vents together 6" above the flood level of the fixtures.