How can you measure how large your pluming pipe is?
Plumbing pipes are measured by their diameter. Simply measure straight across. Pipes are measure either OD or ID which OD = Outside Diameter, and ID = Inside Diameter.
If you don’t know which one to accept a rule of thumb is if it is thick wall PVC it is measured ID, thin wall is OD. It pretty much goes the same with every other type of plumbing also. Copper is thin wall and measured OD whereas steal pipe is thick wall and measured ID.
