--- title: "The Complete Guide to PEX Pipe" description: "PEX pipe is a type of flexible piping used in plumbing. Should use use it instead of copper or steel for your next project?" date: "2018-02-15" modified: "2025-07-17" authors: - name: "Bob Vila" job_title: "Founder" link: "https://www.bobvila.com/authors/bob-vila/" - name: "Timothy Dale" job_title: "Contributing Writer" link: "https://www.bobvila.com/authors/timothy-dale/" url: "https://www.bobvila.com/articles/pex-pipe/" categories: - "Interior" tags: - "101" --- # The Complete Guide to PEX Pipe ![A row of floor heating distribution PEX Pipes.]() *Photo: Halfpoint Images via Getty Images* The type and size of plumbing pipe chosen for any application depends on how the material will be used, the water pressure needs of the home, the drainage requirements, the specific appliance or fixture, and the preference of the homeowner or installer. For instance, PVC and ABS pipes are preferred for drainage and waste systems, while copper, CPVC, and PEX are commonly used for hot and cold water lines, with PEX being a popular option for DIYers who are not comfortable using a blowtorch or soldering. Cross-linked polyethylene (PEX) is a type of flexible plumbing pipe made out of plastic that makes for a great alternative to copper or galvanized steel. You’ve probably seen rolls of blue and red PEX water piping in the plumbing aisle of your local home improvement store, but you might still be wondering exactly what is PEX piping and what is PEX made of. Continue reading this guide to PEX pipe to better understand what PEX pipe is, how it can be used, and why it’s a good choice for DIYers. ## What is PEX pipe? In 1968, German scientist Thomas Engel discovered a way to cross-link common plastic (polyethylene) through radiation to produce a much suppler form of the material. The new plastic, fashioned into flexible PEX pipe (also known as PEX tubing), arrived in the U.S. in the 1980s, initially for [radiant floor heating systems](). Today, PEX is used in more than 60 percent of new construction residential water supply systems. Despite the popularity of the product, what is PEX tubing is still a common question, especially for DIYers who may not have a lot of plumbing experience. In essence, PEX tubing is a type of flexible plastic [plumbing pipe]() used for hot and cold water lines as a substitute for copper. There are several PEX pipe sizes, from ¼ inch to 2 inches, to accommodate a range of applications, and the flexibility of this product makes it an appealing option for retrofitting existing plumbing systems. However, it should be noted that PEX is vulnerable to UV radiation, so it must be stored and installed indoors and away from sunny windows to prevent premature degradation. ## When to Use PEX Pipe ![A woman works to install PEX pipes in a flooring project.]() *Photo: Elena Popova via Getty Images* PEX has a distinct advantage over copper and galvanized steel plumbing because of its flexibility, which allows one end of PEX pipe to connect to a PEX manifold (the main water control system) and then wind through walls and floors—uninterrupted—all the way to an individual fixture. PEX piping is also less susceptible to temperature changes, making it a good choice for homes that may be at risk of [frozen pipes]() since the PEX will expand, rather than crack. PEX can be used for both hot and cold water lines, as well as connections to various water-using appliances and radiant heating applications. If you’re trying to compare PEX pipe to PVC, note that these materials are usually used for different purposes. While PEX is typically for incoming water lines, PVC is generally used for drain lines, so there is no real overlap in use. ## Types of PEX Pipe ![PEX A, PEX B, and PEX C pipes run alongside each other.]() *Photo: Danica O. Kus via Getty Images* The different types of PEX material are also important to consider when answering the question, “What is PEX plumbing?” The three types of PEX—PEX-A, PEX-B, and PEX-C—are classified not by PEX pipe pressure rating or PEX pipe specifications, but instead, by manufacturing method. - **PEX-A** is manufactured using peroxide. It’s the most flexible of the three types and is suitable for use in all home water-supply plumbing needs. It expands to the greatest degree when subjected to cold, so it’s the most resistant to cracking in frigid temperatures. It’s easy to work with, but more expensive than B or C. Other than flexibility, PEX-A has no significant benefit over PEX-B. - **PEX-B** is manufactured using a moisture-cure method. It is slightly stiffer than PEX-A and has a distinct coil “memory” that makes the tubing want to return to its original coiled state. The coil memory, however, is not a hurdle to installation, and PEX-B is often the tubing of choice for residential plumbing because, while it also expands to resist cracking when water freezes, it is less expensive than PEX-A. PEX-B also features an increased resistance to chlorine, making it a good choice in areas where water is highly chlorinated. - **PEX-C** is manufactured via an irradiation method. Because it’s the stiffest version, PEX-C is the most difficult to work with; this stiffness also makes it the most prone to kinking and susceptible to cracking when water freezes. These undesirable traits make PEX-C best suited for short repairs where bending around sharp corners isn’t necessary. PEX-C is the most economical choice. ## PEX Particulars PEX is available in a variety of lengths, from short 10-foot pieces for small repairs to rolls over 500 feet long, which are used for installing a home’s entire water supply system. On average, PEX pipe costs about $0.40 to $4 per linear foot, which is around the same cost as CPVC, which runs about $0.50 to $3 per linear foot. Both PEX and CPVC cost less than copper piping, which has an average cost of $2 to $12 per linear foot. PEX pipe ranges from 3/8 to 1 inch in diameter, and its color-coding makes it a snap to identify what a specific pipe is used for. | **PEX Pipe Color** | **PEX Pipe Function** | | --- | --- | | Red | Carries hot water | | Blue | Carries cold water | | White | Carries either hot or cold | | Gray | Carries either hot or cold | ## Pros and Cons of Using PEX Pipe ![Two sets of red and blue PEX pipes converge.]() *Photo: mikroman6 via Getty Images* As with any home-building product, there are both pros and cons to consider before deciding if PEX piping is right for your project. Check out the benefits and drawbacks of PEX to determine if PEX is a good choice for your home. ### Pros - Installing PEX does not require soldering, while installing copper and galvanized steel does. - PEX expands, making it more resistant to freeze-cracking than either copper or steel. - PEX does not corrode, which can happen with both copper and steel pipes, leading to leaks and contamination of the water supply. - Water flows silently through PEX, eliminating the [“water hammer” noise]() associated with metal piping. - Color coding (red and blue) makes it simple to distinguish hot and cold supply lines. - PEX can be connected to existing metal supply lines with the correct fittings. ### Cons - PEX is not suitable for outdoor use. Ultraviolet rays cause PEX to break down quickly; tubing left outdoors can harden and crack within a couple of months. - PEX is difficult to recycle, but no longer impossible, so it’s often better to repurpose PEX rather than recycle the material. - Though installation is DIY-friendly, working with PEX requires special connectors and tools. Find a list of the necessary tools and connectors below. - PEX piping is [susceptible to rodent damage](), so it’s important that any homes using PEX are free of rodents and other pests that may damage the piping. ## FAQs ## Author Bob Vila is America's Handyman. As a TV host, author, spokesperson, builder and historic preservationist, he has been heavily involved in construction and remodeling for the better part of a half century. ### Author social links [Twitter]() [Pinterest]() [Facebook]() [Instagram]()