The diagram will absolutely have to include a bathroom plumbing vent diagram. Vent pipes on plumbing diagrams are drawn as dashed lines, while pipes that carry water are drawn as solid lines.

These plans call for a 3-inch-diameter PVC pipe for the main drain and the short length leading from the toilet to the drain, and a 2-inch PVC for the other drain lines and the vents.

Q. I have a question about my home plumbing. My home was built in 1975 and has PVC piping. Each time I use the bathroom sink or flush the toilet there is a loud snapping noise in the plumbing where ...

More homeowners could understand the importance of plumbing vent pipes. These pipes provide the pathway air must follow when you flush a toilet, use a washing machine or brush your teeth.