My Plumber made the connection of a new PVC pipe vent to my existing cast iron vent pipe which is in the wall for Toilet. The connection is about 8 inches above the floor. This connection is higher than the toilet or sink drain pipes, because they are all below the floor in the crawl space.
However, the connection is lower than the top of the toilet bowl and lower that the top of the bathroom sink bowl. The connection is made with a mission band.
If there ever was a sewer backup, I want to avoid any water that might enter the vent stack past the connection of the two pipes.
Is my plumber’s connection the correct way?