What is CPVC pipe? What is the difference between CPVC and PVC pipe? How long will CPVC last?

Ask any local Phoenix plumber what CPVC pipe is and they will curse the name. We joke around here that we don’t speak loudly in front of CPVC, only in whispers and before making any repair to CPVC we say a prayer to the plumbing gods. If someone has a home plumbed in CPVC we usually recommend replacing the pipe because it’s history here in the Phoenix area of being brittle and leaking, especially on the hot side.Now let me emphasize this has been our experience of 23 years here in the Phoenix area, I know plumbers in other states that have no issues with CPVC cracking or leaking and use it regularly.

What is CPVC pipe?

CPVC is the abbreviation for Chlorinated Polyvinyl Chloride. I know this sounds very fancy and scientific, and it is, but let’s break this down. Polyvinyl Chloride is the technical name for PVC. We have all seen that white plastic pipe in the hardware store. Well, that is PVC pipe, and PVC pipe can only legally be used for potable water under ground and for cold water only. Scientists figured out that if they add chlorine to the pipe during the manufacturing process then the CPVC pipe can withstand hot water and hold up above ground.

When is CPVC used?

CPVC became a popular alternative to copper for its ease of installation and price point, often being used to pipe the entire water system in many homes and commercial buildings. CPVC has also been used in fire suppression systems and sewer drainage.

How long will CPVC last

There are many resources that state CPVC can be expected to last 50-75 years, and I’m sure somewhere, and in some installations it will, however we see a lot of brittleCPVC that is difficult to repair that is only 10 years old.

So what is wrong with CPVC?

Unfortunately, CPVC has a weakness. CPVC is affected by Hydrocarbons. According to Duane Priddyfrom Plastic Expert Group & Plastic Failure Labs, “many Plumbers are now refusing to install CPVC piping because the pipes and fittings may become brittle after a few years of use forcing them to return and replace the piping. Our work has found that CPVC piping is incompatible with most hydrocarbon chemicals including the solvents in the cement used to make joints in the piping system. If the installer does not meticulously follow the installation rules leaving excessive cement on either the inside or the outside of pipes and/or fittings, the solvents (especially cyclohexanone) migrate into the pipes and fittings causing them to turn brittle.”

Summary

CPVC began being used in Arizona for the potable water pipes in many thousands of homes and businesses, andsome plumbers will still use it due to its price point and ease of installation.Manufactures will tell you that the pipe should last 50 to 75 years, truth is that it is very unlikely. In the Phoenix metropolitan many if not most plumbers have been cursing its use for decades. Hydrocarbons cause CPVC to become brittle over time and to make matters worse you can find them in the cements commonly used to join the pipe and fittings together. I for one am not sure how to avoid that with out another litany of issues. So,in short if you have CPVC in your home it is the humble, or maybe not so humble opinion that it is not a matter of if you are going to have a leak but rather when. We strongly recommend that you re-pipe your home before it floods due to the cracking of a now brittle CPVC.