CPVC or PVC: Make the Right Choice for Plumbing Repairs

If you’ve spent any time in the plumbing aisle at your local hardware store, you’ve probably heard someone ask, “what’s the difference between PVC and CPVC?” While the products have very similar names, they are not interchangeable and getting them mixed up can lead to major headaches on a DIY project. Before you get started, make sure you know the difference between these two materials that may be side-by-side in the plumbing aisle of your chosen store. 

As their names suggest, the two share a similar chemical foundation. But the differences between them are much more important than their similarities when choosing the right material for a home’s plumbing system.

Before we get into the details about those differences, here’s the short form: If you’re repairing the hot and cold water plumbing in your home, make sure to use CPVC. PVC is prohibited by most plumbing codes for use in residential water distribution systems within buildings because of its pressure and temperature limitations. PVC can be used for residential service lines to the building and drain, waste, and vent (DWV) systems, but if you try to use it for water distribution systems within the building, your small repair job could suddenly turn into a much bigger project. 

How PVC and CPVC are Different 

PVC, which stands for polyvinyl chloride, was developed in the 1930s and has been used for everything from vinyl siding to piping for storm sewers. While it proved suitable for some plumbing applications, it couldn’t handle the higher temperatures and pressures that exist within water distribution systems in homes and other buildings. Over the next few decades, scientists addressed the limitations of PVC by adding more chlorine to the PVC molecule, creating chlorinated polyvinyl chloride or CPVC in the 1950s.

In the second half of the 20th century, CPVC became established as an inexpensive and reliable alternative to copper and galvanized iron piping that wasn’t subject to scale, corrosion, or chlorine degradation. In particular, FlowGuard Gold® CPVC, manufactured by Lubrizol Advanced Materials, became America’s most proven non-metallic piping system with more than 12 billion feet installed in homes and businesses across the country. Here’s what CPVC offers that PVC doesn’t:  

• Higher temperature resistance: FlowGuard Gold CPVC has a maximum service temperature of 180° F for pressure applications. PVC is only intended for cold water and has a maximum service temperature of 140° F for pressure applications. Not only can CPVC handle higher temperatures than PVC, but its increased temperature resistance enables it to perform better within PVC’s working range.

• Higher pressure resistance: Burst pressure is a measure of the mechanical strength limit of a pipe and is affected by both pressure and temperature. At room temperature, FlowGuard Gold CPVC is pressure rated to 400 psi. At 100 psi it is rated at 180° F. PVC pipes come in a variety of dimensions and wall thicknesses – each with unique pressure capabilities  – but these systems may fail when exposed to pressure applications above 140° F.  

There’s a reason plumbing codes prohibit the use of PVC in water distribution systems within a building: the temperature and pressures that exist in these systems exceed those of the material, greatly increasing the likelihood of failure. 

Differentiating Between CPVC and PVC 

Now that you understand why you can’t substitute PVC for CPVC in your home, let’s make sure you don’t accidentally pick up the wrong material when you’re shopping for supplies. From a distance, the two can look similar, but there are several ways you can make sure you come home with the right pipes and fittings.  

• Labeling: CPVC pipes should be clearly marked. With FlowGuard Gold CPVC you can look for the distinctive gold stripe on the pipe. When you see that, you know you’ve got what you need. It can be a little trickier with fittings, as smaller fittings like couplings can have labeling that is not easy to read. Particularly when fittings are available unpackaged in a bin, you’ll want to double-check that you’re getting a CPVC fitting rather than a PVC fitting that was dropped in the wrong bin by another shopper.  

• Color: To prevent confusion in the market, manufacturers of CPVC and PVC produce their materials in different colors. CPVC pipes and fittings will be beige or tan while PVC pipes and fittings will typically be white.  

• Sizing: Another way manufacturers prevent confusion is by producing the respective materials using different sizing standards. CPVC is available in copper tube sizes, the standard for residential drinking water systems. PVC is available in iron pipe sizes. This prevents plumbers and homeowners from accidentally using a PVC fitting with a CPVC pipe or vice versa. It also creates one more way you can make sure you are getting the right fitting for your repair job. If you’re not sure the fitting you picked out of a bin is CPVC or PVC, grab a piece of CPVC pipe and test the fit. If the pipe inserts snugly into the fitting, you’ve got the right material. If the fitting sits loosely around the pipe, you probably have a PVC fitting. 

Choosing the Right CPVC 

One more thing to remember when you’re out shopping for plumbing materials: not all CPVC is created equal. FlowGuard Gold pipes and fittings are tested to the highest performance standards and consistently outperform generic CPVC in pressure resistance at higher temperatures and impact strength. FlowGuard Gold CPVC compounds are processed in the U.S.A. to the highest standards for consistent quality and superior performance.

If you’re installing FlowGuard Gold CPVC for the first time, reference our quick installation guide and other training resources. Of course, as valuable as these resources are, they’re no substitute for the training and experience of a professional plumber. For projects beyond minor repairs, we always recommend using a licensed plumber. With the right materials and the right skills, you’ll get a plumbing system you can count on for years.