Some common plumbing pipe sizes are 1/2 to 2 inches diameter for supplying water to homes, 1/2 inch and 1 inch diameters for irrigating residential landscapes, and 1 1/2 inches and 6 inches diameter for drain pipes. Plumbing pipe size varies depending on the pipe material and application.
Copper pipes that are supply water to residences are available in diameters up to 6 inches. For this use, diameters of 1/2 to 2 inches are common. PVC pipes that irrigate home landscapes are available in 1/2 to 6 inch diameter sizes, with the 1/2 and 1 inch diameter pipes being most common.
Cast iron pipes are common for residential drain systems. Acrylonitrile butadiene styrene pipes used for the same purpose have thick walls, with a wall thickness of schedule 40. Normally, drain pipes have a larger diameter than pipes supplying water.