All plumbing pipe must be tested before being certified/rated for its intended use by the National Sanitation Foundation (NSF) and accepted by the building codes. Pipe that is rated for potable water must be designed to be used under pressure and not leach any contaminants from the pipe material into the water. Sewage pipe, also called DWV for “Drain Waste Vent,” does not have to meet those standards, but must be structurally stable and suitable for the disposal of water or wastewater. 

    Pipe that has been approved and rated for potable water will be marked with “NSF-PW” or “NSF-61” in the line of printed data along the side and, obviously, only rated pipe should be installed. Because different PVC pipe can be used for water service pipe to a home (but not inside) or drainage pipe, the PVC pipe rated only for drainage will be marked “NSF-DWV,” which stands for Drain Waste Vent. 

   All green PVC pipe is DWV. See our blog post What is the difference between green and white sewer drain pipes? to learn more.

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Here’s links to a collection of our other blog posts about PLUMBING PIPES:

• How can I protect my pipes to keep them from bursting during a hard winter freeze in North Florida?

• Can galvanized steel pipe still be used for new water lines in a house? 

• How can I tell if I have cast iron pipes in my house? 

• Why can't a sanitary tee be used for a horizontal-to-horizontal drain pipe connection? 

• Is a washing machine drain hose required to be secured at the standpipe?

• What are the abandoned pipes sticking out of the wall in my house?  

• What are the code requirements for plumbing vent terminations?

• What are the code requirements for layout of drain piping under sinks?

• What causes a gurgling sound when a bathtub or sink drains? 

• What is a "combination waste and vent" in a plumbing system? 

• What is a building trap?  

• What is a galvanized nipple?

• What are the pipes sticking out near my water valves?

• How do you accurately find a broken water pipe leak under the floor slab?

• Why is old galvanized steel water pipe a problem for homebuyers?

• What does polybutylene pipe look like? Why is it a problem? 

• Which water pipes are an insurance problem and possibly uninsurable?

• Can you connect CPVC pipe directly to a gas water heater?  

     Visit our PLUMBING page for other related blog posts on this subject, or go to the INDEX for a complete listing of all our articles.