This was a replacement , to replace the identical toilet. I was chasing a sewer odor for months, changed the wax ring 3 times thinking it was the problem. Next I thought it was the toilet itself, bought a new one and odor did not go away. Finally I discovered the vent pipe dropped down into the black water tank. The top of this pipe was not glued or a poor glue joint and separated releasing sewer odor into my bathroom enclosure. Re-inserted,,, problem solved.