great white
New Member
We are in the planning stages of adding bathroom to basement. This new bathroom is directly below existing upstairs bathroom. House is 1 story ranch. Looking for additional opinions. Most of the plumbing contractors are saying, AAV vent for vanity and no other vents required do to close proximity to existing stack. I am also concerned about the toilet drain connecting upstream of shower and vanity. Is there a risk with flow of toilet siphoning out the traps for shower and vanity?