Plumbing Pipe Sizes

Although plumbing materials manufacturers produce pipe to standard dimensions, the diameter of pipes varies greatly according to the pipe's application and the material it's made of. For example, to facilitate gravity fed drainage and accommodate sudden bursts of water, residential drain pipes are substantially larger than standard residential water pipes. You'll encounter a wide range of pipe sizes at the average home improvement store; learn about the sizes commonly applied to residential plumbing and you can choose the right materials for your job.

PVC Pipe

Copper water supply pipes are significantly smaller than plastic drain lines.

Polvinyl chloride, or PVC, typically applies to landscape and agricultural irrigation projects.  Aside from length, PVC pipes vary in wall thickness and diameter.

Manufacturers use the term "schedule" to refer to PVC pipe's thickness, such as schedule 10 or schedule 40; higher numbers correspond to thicker walls.  Additionally, standard PVC pipes range in diameter from 1/2 inch to 6 inches or greater.

For residential landscape irrigation, plumbers commonly use pipe between 1/2 inch and 1 inch in diameter. 

Copper Pipe

Like PVC pipes, copper supply lines vary according to wall thickness and diameter.  Copper pipe manufacturers designate copper pipes' wall thickness by an identifying letter.

For example, type K copper tube has a relatively thick wall and type M has a relatively thin wall.  Copper plumbing pipe is available in diameters as large as 6 inches.

However, for residential water supply applications, plumbers typically use pipe that between 1/2 inch to 2 inches in diameter. 


Acrylonitrile butadiene styrene, or ABS, is a plastic pipe primarily applied to residential drain, waste and vent systems.  Usually black, ABS pipe must carry rushing drain and waste water to septic or sewer systems.

To handle the sudden bursts of activity, ABS pipe is significantly larger in diameter than water supply pipes.  Depending upon plumbing code requirements, ABS drain pipes range from 1 1/2 inches in diameter to approximately 8 inches in diameter.

The ABS available for residential plumbing is typically has a schedule 40 wall thickness. 

Cast Iron Pipe

A common alternative to ABS, cast iron drain pipes are heavy and durable.  Plumbers can use cast iron for all facets of a drain system, include grey water, waste water and vent stacks.

As with ABS, cast iron pipe is available in a broad range of diameters.  Common cast iron pipe sizes for residential applications include diameters between 1 1/2 inches and 6 inches.

About the Author

Based in Hawaii, Shane Grey began writing professionally in 2004. He draws on his construction experience to write instructional home and garden articles. In addition to freelance work, Grey has held a position as an in-house copywriter for an online retailer. He holds a Bachelor of Arts in theater arts from Humboldt State University.

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