How to Determine PVC Pipe Size for a Project

Last Updated: October 8, 2020 References

Before you dive into a project, it's important to understand what kind of PVC pipe you need. PVC pipes vary in diameter as well as flexibility and temperature resistance. After reading this guide, you'll be able to select a PVC pipe with confidence.

Method 1

Method 1 of 3:

Understand the range of PVC pipes you can work with.

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Diameter:^{[1]
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- In the United States, PVC pipes range in diameter from 3/8 to 24 inches (9.53-60.96 cm).
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Schedule (the thickness of a pipe's inner wall):^{[2]
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- PVC pipes normally range from schedule 20 to 80.
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Temperature:^{[3]
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- C900 pipes are used for water mains, where water pressure may exceed 150 PSI (1034.21 KPA).
- CPVCs are rated for higher temperatures (they are also called hot water pipes).
- Cell-cores have the same wall thicknesses as CPVCs but are lighter and less expensive.
- If you plan to use PVC pipes for potable water plumbing, make sure they carry a National Sanitation Foundation seal.^{[4]
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Cost:
- Thinner pipes generally cost less, while thicker pipes cost more.

Method 2

Method 2 of 3:

If your project requires curved surfaces, use pipes with small diameters.

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Schedule 20 pipes (also called DWVs) are the least rigid PVC pipes.
- They are suitable for non-pressurized or low pressure plumbing applications like irrigation systems, sanitary drainage, or for construction projects where flexibility is more important than structural strength.
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1/2 inch (1.27 cm) plumbing grade PVC pipes are also extremely flexible, but they lack strength and can kink when bent. They works well for kites and other light structures.
- The actual exterior diameter of a 1/2 inch PVC pipe is not 1/2 inches, but rather 0.840 inches (2.133 cm).
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3/4 inch (1.91 cm) plumbing grade PVC pipes are very bendable and ideal for any project that requires flexibility, like green houses, pet agility hoops or other curved frames. These pipes will spring back to their original shape if bent.
- The actual exterior diameter of a 3/4 inch PVC pipe is not 3/4 inches, but rather 1.050 inches (2.67 cm).

Method 3

Method 3 of 3:

If your project requires stiffness and strength, use large diameter pipes.

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Schedule 40 is the standard class plumbing pipe for residential and commercial potable water services.^{[5]
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- It can withstand 160 PSI (1103.16 KPA) at 72 degrees (22.22 degrees Celsius) and is suitable for rigid construction projects.
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Schedule 80 is the heaviest standard PVC pipe class.^{[6]
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- The most common use for schedule 80 pipe is in underground electrical conduits. They are very stiff and suitable for rigid frameworks.
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1 inch (2.54 cm) plumbing grade PVC pipes are slightly flexible but still fairly rigid. This pipe is ideal if your project requires minimal flexibility while demanding a strong framework.
- The actual exterior diameter of a 1 inch PVC pipe is not 1 inch, but rather 1.32 inches (3.35 cm).
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1-1/4 inch (3.18 cm) plumbing grade PVC pipes are ideal for very rigid, lightweight projects. They are commonly used to build a strong sturdy platforms, like shelves, tables and walls.
- The actual exterior diameter of a 1-1/4 inch PVC pipe is not 1-1/4 inches, but rather 1.66 inches (4.22 cm).
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1-1/2 inch (3.81 cm) plumbing grade PVC pipes are extremely rigid and heavy, and can be difficult to work with.^{[7]
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- The actual exterior diameter of a 1-1/2 inch PVC pipe is not 1-1/2 inches, but rather 1.90 inches (4.83 cm).
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2 inch (5.08 cm) plumbing grade PVC pipes are extremely strong and will hold weight without bending.
- They are also very heavy and expensive. However if your project requires a good foundation, 2 inch PVC pipes are ideal. They work well for canister-style projects (in conjunction with end caps) like garbage bag holders.
- Note: The actual exterior diameter of a 2 inch PVC pipe is not 2 inches, but rather 2.38 inches (6.05 cm).

Community Q&A

Question

I am looking for the load bearing capability of 2-inch schedule-40 PVC. Specifically, can it be buried at a 24-inch depth and a non-load-bearing building post be placed on top of it with an 8-inch footer poured first on top of the pipe?

Community Answer

I wouldn't use schedule 40 for your particular application. I would use schedule 80; it is much more rigid and is very tough. You can drive heavy equipment or commercial vehicles over schedule-80 PVC if it's buried sufficiently. Use schedule 80 and bury it deeper than 24' inches, if possible, and you shouldn't have any problems.
Question

I want to use two 10' PVC pipes to slide a 41-pound canoe up to car racks. What is the smallest diameter PVC pipe that would be rigid and not break when the canoe is at the midpoint of the pipes?

Community Answer

It is highly unlikely that a PVC pipe will break under such a load; however, it will bend significantly. To avoid this, you can also check out metal fencing pipes that they use to put along the top of chain link. Find the diameter of PVC into which the metal pipe will fit, and use the metal pipe to add strength and rigidity to the PVC. The outer PVC will protect your canoe from scratches.
Question

Can I still buy the old style yellow PVC pipe?

Community Answer

Yes, you can. You can purchase it online.