Markings on PVC Pipe, What they mean and how to read them

PVC Pipe Markings

Standard plumbing grade pvc pipe is is marked with a universal standard code that tells you several things about the pipe.  This marking is required by law in most places so that builders can easily distinguish the properties and tolerances of the pipe the are using.  There is no established color code for pvc pipe so the only way to know exactly what kind of pipe you are working with you need to understand what the markings mean.


So what do the markings on pvc pipe tell us?

The outside of all plumbing grade pvc pipe is labeled with the following information:

  • Manufacturer of the Pipe
  • The Standard the Pipe Conforms to
  • Pipe Size
  • Pressure Rating
  • Schedule Number
  • A Laboratory Seal or Mark if it is to be used for potable water


Though it is not required, another common marking found on pvc pipe is its maximum temperature tolerance.  Keep in mind when building with pvc that the size marked on the pipe is for the inside diameter, while the pvc schedule number refers to the wall thickness of the pipe.  Also keep in mind that even if the pipe is marked as 1.25″, this is not the actual outside diameter of the pipe.  This is due to nominal pipe size standardization.  I won’t bore you with the specifics of NPS but remember when buying fittings or joining two pieces of pvc together to actually measure your pipe to ensure you get the right size.  Or better yet consult the following chart.


PVC Pipe Actual Size Conversion Chart

Marking Size Actual Size Decimal
1/2″ 13/16″ .840
3/4″ 1 1/6″ 1.050
1″ 1 5/16″ 1.315
1 1/4″ 1 5/8″ 1.660
1 1/2″ 1 7/8″ 1.900
2″ 2 3/8″ 2.375

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