Plastic Pipe 101: CPVC vs. PVC vs. PEX

Plastic piping is known for benefits including affordability, faster and more flexible installation, and durability, but do you know the difference between various plastic pipes? What is the best material for water pipes?

 

When determining which pipe and fitting material is best for your home build or remodel, there are certain key factors to consider. Your builder, contractor and local officials are great resources, but knowing some of the basics will make those discussions more productive.

 

PVC, CPVC and PEX Explained

 

PVC — Polyvinyl Chloride

A plumbing mainstay since the 1960s, PVC is the most widely used plastic piping in the plumbing and construction industry. In the U.S., PVC is made from natural gas and salt (yes, “salt”). Learn more about PVC’s history and how it’s made. PVC is corrosion-resistant and widely accepted by building codes for most piping applications (except hot water).

 

CPVC — Chlorinated Poly (Vinyl Chloride)

CPVC (chlorinated poly (vinyl chloride) is a strong and rigid thermoplastic material that is used for hot and cold potable water applications in residential construction. Because of its makeup, CPVC is immune to damage from highly chlorinated domestic water and has a higher temperature tolerance than PVC. Chlorine-based disinfection is used by water companies to kill disease-causing bacteria before water enters your home. Depending on your location and time of year, disinfection methods and levels in water systems can vary without notification. CPVC is corrosion-resistant. 

 

PEX — Cross-linked Polyethylene

PEX is a flexible plastic material made from medium- or high-density polyethylene. PEX piping has been used in hot- and cold-water distribution systems and for hydronic radiant heating in Europe for decades. Introduced into the U.S. in the 1980s, PEX is the most widely used flexible piping for plumbing and radiant floor heating applications. Due to its flexibility, it’s often a popular choice for remodels because it can be easily snaked through the walls. PEX tubing is recognized as acceptable for water distribution piping in all major model plumbing codes. Learn about the PEX manufacturing process.

 

Comparing PVC, CPVC and PEX

 

How PVC, CPVC, and PEX Are Used in the Home

 

Plumbing pipe is primarily used in three ways in your home, to:

1. Bring water from the local water utility to your house through water service lines.

 

1. Deliver hot and cold drinking water to your faucets, showers, toilets and appliances through water distribution systems inside your home.

 

1. Collect and remove water, sewer gases and waste from toilets, showers, sinks and appliances through drain-waste-vent (DWV) systems.

 

Based on these three functions, PVC, CPVC and PEX may work for some applications, but not others. 

 

While PVC is excellent for water service lines and DWV applications, it’s not recommended for hot-water distribution systems because it can only withstand temperatures up to 140℉. CPVC and PEX, however, can withstand temperatures up to 200℉. Most water heaters are set to heat water to no more than 140℉. 

 

Here’s an overview of some of the common ways PVC, CPVC and PEX can be used in the home. (Always check your local building codes to see what’s approved for your application and area.)

 

   

PVC

 CPVC

 PEX

Water service lines  

✅

 

✅

✅

  Water distribution systems  X  

✅

 

✅

Average Lifespan

PVC, CPVC and PEX have been in use in residential plumbing applications for decades. Historical information, as well as independent research studies, indicate that PVC, CPVC and PEX can have a 50+ year life when installed correctly under the proper conditions.

 

Are CPVC, PVC & PEX Safe for Drinking Water?

 

All plastics used in potable water systems must be tested regularly and certified by a third-party certifier as meeting the strict public health requirements of NSF/ANSI/CAN 61. NSF International is an independent, accredited organization that develops public health standards and certification programs to help protect the world’s food, water, consumer products and environment. This testing ensures that drinking water carried by plastic pipe meets the strictest health effects standards. You can look for the NSF (or other third party) certification to rest assured that your piping choice is safe for drinking.