PEX Plumbing Pipe: Everything You Need to Know (2022)

    Home Skills Plumbing Pipes

    PEX Plumbing Pipe: Everything You Need to Know (1)Family HandymanUpdated: Mar. 31, 2022

      PEX piping is the biggest revolution since the flush toilet. Learn what it is and everything in between with this PEX plumbing guide.

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      PEX Plumbing Pipe: Everything You Need to Know (2)IcemanJ/Getty Images

      What is PEX Piping?

      PEX piping (shorthand for cross-linked polyethylene) costs less than half the price of copper and installs much faster. And since it’s flexible, PEX makes remodeling jobs easier. PEX has a strong “memory;” it always wants to spring back to its original shape. So working with a coil of PEX is like wrestling with a giant Slinky. For most jobs, you’re better off buying 10-ft. “sticks” instead. You may have to pay a few cents more per foot and install a coupler or two, but you’ll avoid frustration and kinks. Even plumbers who run miles of PEX every year often buy sticks than coils.

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      PEX Plumbing Pipe: Everything You Need to Know (3)Family Handyman

      Which is Better – PEX or Copper?

      PEX has several advantages over copper pipes:

      • PEX is cheaper than copper. Half-inch PEX tubing costs about one-third the price of copper. Some of the savings will go towards purchasing a special tool to install the fittings. But if you’re doing a medium-to-large plumbing job, you’ll usually save on PEX over copper.
      • PEX fittings are faster to install than copper. If you use a manifold and ‘home-run’ system, it’s like running a garden hose to each fixture — super fast and easy. But even if you install PEX fittings in a conventional main line and branch system, the connections are quicker to make than soldering copper.
      • A PEX supply won’t corrode like copper. If you live in an area with acidic water, copper can corrode over time. A PEX supply is unaffected by acidic water and is therefore a better choice in these areas.

      Watch this video to learn more about the PEX revolution:

      (Video) The 5 BIG MISTAKES Beginners Make When Installing PEX (Watch Before Installing!) | GOT2LEARN

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      PEX Plumbing Pipe: Everything You Need to Know (4)Family Handyman

      What About PEX vs. CPVC?

      A PEX supply and CPVC cost about the same. But there are a few reasons why PEX may be a better choice. First, a PEX doesn’t require glue, which means you don’t have to work in well-ventilated spaces or wear a respirator. PEX is less likely than CPVC to burst if it freezes. Also, since PEX is more flexible and available in long lengths, it can work better for ‘fishing’ through walls in remodeling situations.

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      PEX Plumbing Pipe: Everything You Need to Know (5)Family Handyman

      Do I Need Special Tools?

      Yes. When plumbing with PEX, you can use stab-in or compression fittings to make the connections, but they’re too expensive to be practical on large projects. Connections for most PEX supply jobs require a special tool. There are several PEX supply connection methods, but only two affordable enough to be practical for DIYers: crimp rings and cinch clamps.

      Crimp rings are a band of metal, usually copper, that you slip over the fitting and compress with a crimp ring tool. The main drawback is that you’ll need either separate crimping tools for one-half inch and three-quarter inch fittings, or a universal tool with a swappable insert (not shown).

      Cinch clamps work more like the traditional band clamps you’re probably familiar with. You slip the cinch clamp tool over the protruding tab and squeeze to tighten the cinch clamp. The same tool works for all sizes of cinch clamps.We like the one-handed version shown in the photo because you can hold the ring in place with one hand while tightening it with the other.

      The only other special tool you need is a scissors-like cutter for the tubing.

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      PEX Plumbing Pipe: Everything You Need to Know (6)Family Handyman

      How Do I Splice PEX Fittings Into My Existing Pipe?

      There are several methods. The easiest is to cut out a section of plumbing pipe and slip in a stab-in tee (left). SharkBite is one common brand of stab-in fitting. This method doesn’t require soldering, which can be a big time-saver. But check with your plumbing inspector if you’re planning to bury this connection in a wall or ceiling. Some areas don’t allow stab-in fittings to be concealed. Another method is to solder in a tee and a PEX supply adapter. Then slip the PEX supply tubing over the adapter and attach it with your chosen connection method (right). You can also use a stab-in tee to connect PEX fittings supply to CPVC. Read the label to find the compatible fitting.

      (Video) PEX Pipe Installation - ALL Connections To Fittings In A WHOLE HOUSE!

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      PEX Plumbing Pipe: Everything You Need to Know (7)Family Handyman

      Do I Have to Use Manifolds with PEX?

      No. You can install PEX fittings supply just like you would other pipe, with main lines and branches to each fixture. But you lose a lot of the benefits of PEX with this system since it requires so many fittings. With the home-run system, you install a manifold in the utility room or some area that’s close to the main water line and water heater, and run a separate PEX tube to each fixture as shown above. This system uses more tubing, but is fast and only requires two connections: one at the manifold and another at the fixture end. You can also use a hybrid system where you run three-quarter inch hot and cold lines to a set of fixtures — for example, a bathroom — and install a smaller manifold behind an access panel. Then make short runs of one-half inch PEX water line tubing to each fixture.

      Manifolds look intimidating. But they actually simplify plumbing runs and reduce possible leaks by eliminating the need for tees and other fittings between the main supply line and the fixture.

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      Does it Meet Code?

      There is no unified national plumbing code. Before starting your PEX plumbing job, check with your local inspector for specific local requirements.

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      PEX Plumbing Pipe: Everything You Need to Know (9)Family Handyman

      Do I Have to Use Red for Hot and Blue for Cold?

      PEX comes in red and blue colors to help you keep track of the hot and cold lines. You can use white PEX for everything if you prefer.

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      PEX Plumbing Pipe: Everything You Need to Know (10)Family Handyman

      Is PEX Reliable?

      PEX has been used for decades in other countries, where there are thousands of homes with 30-year-old, leak-free PEX. Most of the problems with PEX systems, in the United States and elsewhere, were due to sloppy installation or faulty fittings rather than the tubing itself.

      (Video) What You Need to Know About PEX Pipe

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      PEX Plumbing Pipe: Everything You Need to Know (11)Family Handyman

      Can I Connect PEX to My Water Heater?

      PEX can’t be directly connected to a water heater. First extend a pipe 18 in. from your water heater and connect the PEX to the pipe.

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      PEX Plumbing Pipe: Everything You Need to Know (12)Family Handyman

      Which Tubing Should I Use for Interior Water Lines?

      For water lines there are three PEX supply grades: PEX-A, PEX-B and PEX-C. They’re manufactured differently, PEX-A being slightly more flexible. If you’re ordering online, go ahead and spend a few cents extra for PEX-A. But don’t go running around town looking for it; the difference isn’t that big. The plumbers we spoke to said they were willing to use any of the types in their homes. PEX is also popular for in-floor radiant heating systems, though you need PEX tubing with an oxygen barrier.

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      PEX Plumbing Pipe: Everything You Need to Know (13)Family Handyman

      How Do I Connect PEX to my Plumbing Fixtures?

      There are several methods. If the connection will be visible, like under a wall-hung sink, and you would prefer the look of a copper tube coming out of the wall, use a copper stub-out (left). You can connect a compression-type shutoff valve to the one-half inch copper stub-out and then connect your fixture. In areas that are concealed, like under a kitchen sink or vanity cabinet, you can eliminate a joint by running PEX supply directly to the shutoff valve. Use a drop-ear bend support to hold the tubing in a tight bend (right). There are several types of shutoff valves that connect directly to PEX.

      (Video) PEX Pipe Installation Tips for Beginners

      If you’re using a manifold system with valves, you may not need to install a shutoff valve at the fixture. Ask your plumbing inspector. We recommend adding one, though. It doesn’t increase the cost much and is more convenient than running downstairs to shut off the water when a repair is needed.

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      What About Expansion?

      PEX supply expands and contracts more than copper, so don’t stretch it tight. Let it droop a little between fasteners. On long runs, it’s a good idea to install a loop as shown to allow for contraction. Another advantage of the loop is that if you mess up and need a little extra tubing, you can steal it from the loop. Also, since PEX moves as it expands and contracts, make sure to drill oversize holes through studs or joists so it can slide easily. And don’t use metal straps to attach it. Use plastic straps instead.

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      PEX Plumbing Pipe: Everything You Need to Know (15)PHOTO: COPYRIGHT EASY HEAT INC.

      Will PEX Break or Split if it Freezes?

      Probably not. Manufacturers are reluctant to say so, but reports from the field suggest PEX can withstand freezing. You should still protect the tubing from freezing. But since it can expand and contract, it’s less likely to break than rigid piping.

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      What if I Goof? Can I Take it Apart?

      Sure. There’s a special tool for cutting off crimp rings, and you can use side cutters to remove cinch clamps. But a rotary tool (Dremel is one brand) fitted with a cutoff blade works great for cutting either type of connector (see photo). After you remove the crimp ring or cinch clamp and pull the PEX supply from the fitting, cut off the end of the tubing to get a fresh section for the new connection. If you damage the fitting with the rotary tool, replace the fitting rather than risk a leak.

      Originally Published: March 31, 2020

      (Video) PEX Pipe: Plumbing for Homeowners

      FAQs

      What should you not do with PEX? ›

      No single pipe/tubing system used in the US has been 100% problem free, and PEX is no exception. Some of the disadvantages of PEX include: It cannot be used outside. It cannot be recycled.

      How many years will PEX last? ›

      PEX: Due to its flexibility and durability, PEX piping should last at least 50 years. PVC / CPVC: Under typical conditions, these pipes should last up to 100 years. Keep in mind that PVC pipes are often used for drainage because extreme heat can damage them.

      Is there a difference between blue and red PEX? ›

      There are no performance differences between red, white, blue and white PEX and all are intended for use in potable water systems. The colors can be used to easily distinguish between hot and cold distribution lines.

      Is PEX OK for drinking water? ›

      There are no health risks associated with drinking water from PEX pipes. A few types of PEX-pipe may cause prolonged undesirable taste and odour if the water remains in pipes over time.

      Do plumbers like PEX? ›

      All this makes PEX an excellent piping material for hot and cold water systems, especially since it is flexible and well adapted for temperatures below freezing all the way up to 200 degrees Fahrenheit. PEX is easy for plumbers to install and has fewer joints, bringing your costs down.

      Can rats eat through PEX pipe? ›

      PEX Pipe Is Vulnerable

      Rodents Chewing Through PEX Pipe is a common problem in our area. It doesn't matter how old your home is, if you have an attic, you need to watch for rodent damage to PEX Pipe or PVC. If you're hearing rustling noises coming from the attic, it's time to do an inspection.

      Is it worth replacing copper pipes with PEX? ›

      Coupled with low production and shipping costs, the savings resulting from installing PEX instead of copper pipes can be significant. Better Energy Efficiency – PEX has a lower thermal conductivity rate than copper. As a result, PEX pipes can help keep hot water hotter for longer periods of time.

      Is PEX A or B better? ›

      Flexibility - PEX-A is the most flexible, allowing for it to be fastened by cold expansion, which allows the end to be fluted prior to inserting the fitting. PEX B is not expandable and you should never expand the end of a PEX-B pipe. Kink-Resistance - PEX-A has the greatest resistance, PEX-B the lowest.

      Whats better PVC or PEX? ›

      PVC has a predicted lifespan of 50-70 years or more, compared with 40-50 years for PEX. - Lower cost. PVC is less expensive to purchase than PEX, although it usually will cost you more in labor.

      Will bleach hurt PEX pipe? ›

      It has been found that chlorine can cause oxidation on the inner wall of PEX piping, eventually resulting in failure. As with any plastic pipe, ultraviolet (UV) light can break down the stabilizers in PEX, causing the pipe to become brittle and eventually fail.

      Are PEX clamps or crimp better? ›

      Pinch Clamp Tools Work Better in Tight Spaces

      Especially when your PEX is pressed up against a wall—or there is just otherwise very little wiggle room to work—crimp tools can become a much bigger hassle. The larger jaw of the tool means you need ample room behind your PEX to be able to make a proper connection.

      Is it OK to use blue PEX for hot water? ›

      Color-Coded: Red PEX pipes can be used for hot water supply lines, blue PEX for cold water supply, and white for either hot or cold. These colors are just for your convenience. Plumbing code does not require the pipe color to match the type of water supply.

      Can PEX freeze? ›

      Due to its flexibility, PEX can expand under the damaging pressure caused by ice formation. If the weather gets cold enough, PEX pipes can and will freeze like any plumbing. However, PEX may be less likely to rupture as a result of freezing.

      Which PEX is best? ›

      Bottom line, PEX A is more resistant to burst pressure than PEX B. PEX A's expansive material can handle up to 500 PSI, which makes it reliable in extremely cold temperatures. Since PEX B is a more rigid material, it will not hold up as well in similar situations.

      What size PEX is used in homes? ›

      PEX is available in 3/8- to 1-inch diameters. It's a good idea to install 1/2-inch or 3/4-inch PEX for your main lines for adequate water flow. When replacing old water supply lines with PEX the standard is to use the same size plumbing, although you can transition from 3/4-inch to 1/2-inch plumbing with an adapter.

      Can I use PEX for shower plumbing? ›

      Use threaded PEX water line fittings for shower valves. Tighten the fittings before crimping the PEX water line. A plastic bracket forms the sharpest 90-degree angle permitted for this brand of PEX.

      Can PEX pipe burst from freezing? ›

      Frozen PEX Pipes Have a Unique Reaction. Due to its flexibility, PEX can expand under the damaging pressure caused by ice formation. If the weather gets cold enough, PEX pipes can and will freeze like any plumbing. However, PEX may be less likely to rupture as a result of freezing.

      Does PEX leach chemicals? ›

      One of the most recent studies, conducted in 2021, tested water from eight different types of PEX pipe brands. They found that 62 chemicals leached into the water, with half of those organic compounds leached considered toxicological but not carcinogenic.

      Will bleach hurt PEX pipe? ›

      It has been found that chlorine can cause oxidation on the inner wall of PEX piping, eventually resulting in failure. As with any plastic pipe, ultraviolet (UV) light can break down the stabilizers in PEX, causing the pipe to become brittle and eventually fail.

      Videos

      1. UPONOR ProPEX, The Future of Plumbing (COMPLETE GUIDE) | GOT2LEARN
      (Got2Learn)
      2. How to Install PEX Pipe in Bathrooms (Quick Tips) -- by Home Repair Tutor
      (Home Repair Tutor)
      3. A lesson about basic PEX plumbing materials - Intro to Plumbing Systems
      (TEACH Construction Community Education)
      4. Is Copper Better Than PEX? (COMPLETE GUIDE) | GOT2LEARN
      (Got2Learn)
      5. PEX-A vs PEX-B - What's the Difference? Which Should You Use?
      (Roger Wakefield)
      6. HOW TO INSTALL PEX PIPE - WHY PEX PIPE IS BETTER AND CHEAPER THAN COPPER PIPE
      (TipsNNTricks)

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