What is PEX Pipe – The Ultimate Guide for Plumbers

Have you ever heard of PEX piping?

Maybe you are wondering what it is and what importance it is to you as a plumber. We’ve got you covered because, in this guide, you will learn everything there is to know about PEX pipes.

What is PEX Pipe?

PEX pipe is a flexible cross-linked polyethylene tubing that comes in various colors for excellent plumbing options.

PEX pipes can be used for both commercial and residential plumbing applications.

PEX Pipes
PEX Pipes

Advantages of PEX Piping in Plumbing Systems

PEX pipe is becoming the most popular option for plumbing applications due to its various benefits. Let’s take a look at some of these benefits in details.


While other types of piping materials need fixtures and fittings for every branch, PEX doesn’t. PEX pipe is flexible in a way that a single pipe can be used for the whole cold-water piping; running from the main source through the walls and floors to the outlets. The same is true with the hot water piping using PEX.

Corrosion Resistance

When your water pipes corrode, you get several leaks and water contamination, which is not good for your household or business. However, with PEX piping you can be able to prevent both leakages and water contamination since it doesn’t corrode.

Conserves Energy

With great thermal conductivity properties, PEX pipes are a better choice for your plumbing solutions because they will preserve energy and help you cut on bills.


Everyone wants to save some money even as they get quality products or services. With PEX pipe you get both quality and affordability. PEX pipe prices are significantly lower than copper pipes prices.


Any material that has expansion as a feature can withstand diverse weather changes. PEX can expand when the pressure or weather changes hence it can resist free-cracking better than other pipes.

Easy Installation

With PEX pipe you won’t need a lot of tools and materials during installation. For instance, no need for soldering torches or glue. This is because PEX is flexible and can bend easily around corners hence no need for joints or fittings.


Generally, PEX material is lightweight, and pipes made from PEX are light and easy to transport to various locations.


Research shows that a properly installed and well-maintained PEX pipe can last for over approximately 50 years. The durability is mainly contributed by the fact that PEX pipes can resist corrosion preventing leakages.

Noise Resistance

Normally, when water flows through metal pipes, the spooky noise produced by the flowing water can make you uncomfortable. However, with PEX piping, you don’t need to worry about any water hammer noise because water flows through them without a sound.

Color Codes

Any product that is color-coded is easy to handle and install. PEX pipe color codes makes it easy for plumbers to identify which pipe goes to which part during installation or repair.

Limitations of PEX Piping

Expertise During Installation

When we say PEX is easy to install, it does not mean that anyone can do it. A lot of errors can occur during installation if you don’t engage an expert for this job.

Heat Damage

During installation, you need to ensure that PEX pipe is not installed to water heaters because PEX will fail when exposed to high-heat conditions.

Only Suitable for Indoor Use

PEX pipe needs to be protected from UV rays at all times because if exposed, the UV rays can cause breakage to the pipes.

Permeability and Damage

PEX pipe can absorb other liquids like chemicals when it is exposed to them, this may lead to water contamination. Another limitation is that since PEX is rubber-like, animals such as rodents can chew through it creating damages that can lead to leakages.

Not Recyclable

Unfortunately, PEX material cannot melt like other plastic materials do. For this reason, it is currently not a good candidate for recycling.

Colors in PEX Piping

Earlier, while we were discussing the benefits of PEX pipe, we mentioned color codes. PEX pipes come in different colors signifying two main uses; hot and cold-water pipes. Let’s take a look at what each PEX pipe color does.

Red PEX Pipe

Red PEX pipe is identified as one that carries hot water, that is its color code.

Red PEX pipes
Red PEX pipes

Grey PEX Pipe

Gray PEX pipe can signify either cold or hot water flow depending on the manufacturer.

Grey PEX Pipes
Grey PEX pipes

Blue PEX Pipe

Generally, blue PEX pipes are used for cold water piping for easy identification.

Blue PEX Pipe
Blue PEX Pipe

White PEX Pipe

As we said earlier, some manufacturers or plumbers may not see the need for color codes or identification. Therefore, white PEX pipes can be used for either cold or hot water situations.

White PEX Pipes
White PEX Pipes

Types of PEX Piping for Plumbers

Plumbers can now choose from any of the three types of PEX pipes available in the market depending on the application conditions.

PEX-A Pipe

PEX-A pipe is produced using peroxide and is the most suitable for almost all water needs at home because it is the most flexible of the three.

Also, its expansion properties are better than PEX-C making it more resistant to cracking under freezing weather conditions. Compared to the other two PEX pipes, PEX-A is the most expensive, however, it is still cheaper than copper or steel pipes.

PEX A pipe
PEX A pipe

PEX-B Pipe

PEX-B pipe is produced through a moisture cured process and is stiffer than PEX-A pipe but more flexible than PEX-C pipe.

Its expansion properties are similar to those of PEX-A pipe and therefore can resist cracking under freezing conditions. PEX-B pipe also has a better resistance to chlorine in water.

PEX B pipe
PEX B Pipe

PEX-C Pipe

PEX-C pipe is produced through an irradiation process and it being the cheapest of the three pipes is also the stiffest and can crack easily under freezing conditions. Since it does not bend easily, it is recommended for repairs that don’t require bending.

PEX C pipe
PEX C Pipe

Best Insulation for PEX Pipe

Like most pipes, PEX pipe requires insulation because when exposed to extremely low temperatures it can freeze. To avoid such expensive damages, you may want to use a good insulation material to protect your pipes.

Experts have recommended the use of foam as an insulator for PEX pipe because it is as flexible as PEX itself. Foam also works well with PEX pipes.

Temperature Rating for PEX Pipe

Every plastic material has a higher and a lower temperature limits that if exceeded may lead to the destruction on the material.

PEX pipe for instance, can serve as a hot water line in plumbing applications. However, the temperature limit for any PEX is at 180o F. exposing PEX to temperatures beyond this would a good way to destroy it.

PEX pipe is also free resistant and can stand the extreme freezing conditions during winter seasons.  However, since PEX is not freezeproof, it may burst when temperatures fall below 20o F.

Pressure Rating for PEX Pipe

Generally, the maximum allowable water pressure for residential plumbing solutions should be at 80 psi. However, PEX pipe can stand pressures of up to 160 psi at 73o F and 100 psi at 180o F.

PEX Vs. Copper Piping

Initially, copper piping was the main plumbing solution available to plumbers. However, over the years, many people are now adopting PEX piping as alternative to copper piping. These two piping options have different strengths and weaknesses. We will discuss some of the aspects that would lead you into choosing one and not the other.

Copper Piping
Copper Piping


Under the benefits of PEX pipe, we had mentioned that PEX pipe can last for approximately 50 years if properly installed and well maintained. It is important to note that a poorly maintained PEX pipe can get damaged after a few years of usage.

Copper pipes are also long-lasting and can serve for over 50 years. However, the secret is proper maintenance.


When comparing costs for metallic and plastic products, usually, the metals cost more. Since copper is a metal, it means that the pipes made from copper are more expensive that those made from PEX which is a plastic. Copper pipes will be three times more costly compared to PEX pipes.


We also mentioned the fact that PEX cannot be recycled since it is cross-linked. However, waste PEX pipes can be used for other purposes like filling traffic barriers or playground equipment.

Copper on the other hand, is highly recyclable and can be melted down and used to make new water pipes.


Flexibility is the one feature that sells PEX pipe more than it does the rest of the piping materials. PEX pipe allows you to navigate your piping around obstacles and does not require extra fittings.

Copper piping on the other hand is not flexible at all, you will need more tools and materials to get your piping done.

PEX Vs. CPVC Piping

The main similarity between PEX and CPVC piping is that they are both made of plastic materials. Beyond this, we can only talk of differences.

They both have their own unique strengths and weaknesses and choosing one and not the other will be determined the application needs. Let’s take a look at some of the aspects that give them separate identities.

 CPVC Pipes
CPVC Pipes

UV Resistance

UV rays from the sun or other sources like lightbulbs can easily destroy plastic parts just like they can human skin. However, some plastic types have a higher resistance to UV rays than others.

For instance, CPVC can last longer than PEX when exposed to UV rays because it is more resistant to them. So, if you need to choose between the two for outdoor use, go for CPVC but it also has to be protected from direct sunlight.


PEX may be cheaper than copper in terms of material and installation cost but it is a bit expensive than CPVC. So, if you have a fixed budget, you may want to consider CPVC. Remember to consider the other factors before choosing the cheapest option available.


Both PEX and CPVC pipes are flexible and easy to install. However, PEX is a better choice because it is available in longer lengths and can maneuver through walls during remodeling.

Freeze Resistance

PEX pipes offer a better resistance to freezing than CPVC pipes because most times, PEX does not burst when frozen.

Water Quality

Good water quality is assured when the pipe that supplies water into your home does not leach substances or chemicals into the water. CPVC is known to offer the best water quality since it does not leach substances into the water.

On the other hand, PEX pipe has the potential to leach substances like ETBE and toluene into the water hence contaminating it. Also, PEX pipe is permeable and may lead to water contamination from

Chlorine Resistance

Under normal conditions, PEX offers resistance to chlorine degradation. However, under certain conditions, PEX can be degraded by chlorine.

On the other hand, CPVC has an element of chlorine in its molecular structure and I therefore more resistant to chlorine degradation.

Estimating PEX Piping Cost

PEX pipes for new installation or replacement may cost the same amount as both will require new pipes and the same installation process.

Currently, PEX pipe costs range from as low as 20 USD to 800 USD depending on the pipe diameter and type of PEX used. Meaning that the price per foot ranges from 50 cents to 2 USD.

Installing PEX pipes at home could cost something from 4,200 to 6,000 USD. However, costs may go down or up depending on factors such as the size of the house, number of fixtures, pipe accessibility, etc.

You may also incur other costs as follows;

  • PEX toolkits go for approximately 90 to 150 USD.
  • Special tools may cost around 50 to 200 USD.

How to Cut PEX Piping System for Plumbing

You may be asking yourself why we need to cut PEX pipe for plumbing. PEX pipes come in coils that are long measuring up to 300 feet. At some point, you will need to cut it during installation. Let’s now talk about what you need for this job.

  • Pipe cutter
  • PEX pipe
  • Deburring tool
  • Measuring tape
  • Marker pen

Once you have assembled all the requirements for PEX cutting process, you are ready to start cutting.

Step One: Measuring the PEX Pipe

Remember your PEX pipe can be of any length as desired. However, before taking measurements, you need to stretch out the pipe over a flat surface. Use a tape measure to take measurements as desired. It is advisable to add an extra inch to every measurement to allow for flexibility during installation.

Step Two: Marking the Measurements

After taking the measurements, you need to mark them using a pen that will not rub away to avoid repeating it all over again.

Step Three: Cutting the PEX Pipe

When cutting PEX pipes, you need to place the cutting blade exactly over the points you marked earlier for accuracy. Once the blade is in place and you feel that you have a good grip, go ahead to cut the pipe by squeezing the cutter firmly and steadily.

Step Four: Deburring the PEX Pipe

A freshly cut pipe may have sharp edges on both the interior and exterior sections. To remove such sharp edges, you need a deburring tool and the process is known as deburring. Deburring of PEX pipe is achieved by sliding the tool at an angle over the sharp edges.

Quality Standards for PEX Piping in Plumbing

PEX pipe has also undergone quality tests and every manufacturer must ensure that their pipes meet a set of quality standards. The most important PEX pipe standards are mentioned below;

  • ASTM F877- The standard certification for PEX pipe cold and hot-water systems.
  • ASTM F876 – The standard certification for tubing.
  • ASTM F2023 – The standard that shows the level of resistance to chlorinated water under high temperatures.
  • ASTM F2657- Standard test to measure resistance to weathering of PEX when outside.
  • ASTM F2788 – The standard certification for inch-sized and metric in PEX pipes.
  • CSA B137.5 – The pressure application standards for PEX pipes.

Choosing Correct PEX Pipe Size for Any Application

PEX pipes usually come in ¾ or ½ inch diameters and each of them is suitable for different functions. For instance, a ¾ diameter can be used to deliver hot water from a heater (but at 18 inches away from the heater) while ½ inch diameter PEX pipe can be used for branching lines.

In terms of length, PEX pipes are available in a range of lengths from 100 to 500 feet. However, it is also possible to buy PEX pipes of shorter lengths like 5 to 10 feet long.

Let’s discuss some of the necessary factors to consider before choosing PEX pipes of any length or diameter.

Length of Runs

If the water has to run over longer distances within the PEX pipes, you may consider getting larger pipe sizes for your installation.


Money is also a key factor for every purchase you make. You may hope to get a thicker PEX type like type A which is more expensive than the rest. However, if it doesn’t fit your budget you may choose to go for PEX-B OR C pipes.

Water Pressure

The intended water pressure will help you decide if you need a thicker PEX pipe or a thinner one. High water pressure requires a thicker PEX tubing to be able to handle the pressure.


Thicker PEX pipes may be able to withstand extreme freezing conditions better than thinner pipes.

Practical Uses of PEX Pipes

PEX pipes are applicable for both commercial and residential applications. Some of these applications are mentioned below.

Plumbing Applications

PEX pipes are currently the best hot and cold-water supply solutions available. It has gained popularity due to benefits like resistance to corrosion, durability and flexibility.

Heated Floors

PEX pipes are adaptable and flexible making them the best candidate for crawl or slab space applications.

Irrigation Systems

Outdoor irrigation systems can now adopt PEX pipes by passing them through the ground to avoid exposure to UV rays.


Since PEX pipe has known resistance to freezing and can stand extremely low temperatures, it has become a better choice for cooling systems.


1. How long does PEX Piping Last?

PEX pipes are durable and can last for up to 50 years with proper installation and maintenance. However, if not properly maintained, PEX pipes can get damaged within 5 years or less.

2. Are PEX Pipes Freeze Resistant?

PEX pipes can resist freezing to a certain extent but they are not freezeproof. However, with proper insulation, PEX pipes can stand extremely low temperatures.

3. Are PEX Piping Best for Outdoor and Indoor Use?

PEX pipes are suitable for indoor applications. This is because exposure to direct UV rays from the sun causes them to age and get cracks.


PEX pipe offers significant benefits over copper or aluminum pipes. It has now become a popular choice among plumbers for both residential and industrial plumbing solutions.

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