What size vent pipe is needed for a toilet?
In short, the UPC wants the sewer of the building to be ventilated correctly. Therefore, a ventilation pipe of the same diameter as the sewer of the building must be connected by the drainage system, and extend through the roof, not diminished in size. One popular way to meet this requirement is by a water bath with a ventilation of 3 or 4 inches.
FREE Virtual Home Repair
We'll diagnose your issue over call or video and virtually walk you through the repair — all for free if you're a new customer! .