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PEX Pipe for Outdoor Use – Everything You Need to Know

Copper pipes have long been the go-to solution for outdoor plumbing because they are durable and harmless to the environment.

However, cross-linked polyethylene (PEX) pipes are replacing them for residential use.

With outdoor PEX tubing, we can install long-lasting pipes for our homes in a cost-efficient and durable way.

In this blog, we will discuss PEX pipes in detail and highlight the best method to use PEX for outdoor purposes.

Before we start, there are a few important things that you should know about before using PEX outdoors, so let’s dive a bit deeper into the topic!

What Is A PEX Pipe?  

Cross-linked polyethylene (PEX) pipes are flexible tubes that can be used for long runs throughout the house.

They are a great alternative to traditional pipe materials like copper and galvanized steel for water lines as they do not need any joints or elbows to bend.

It makes them a highly desirable option for residential properties.

PEX pipes can be easily found at any local hardware store.

In fact, users do not need a plumber to install these pipes as they can replace them independently.

If it’s a leaky water line inside the house, a person can replace the old pipes with PEX, and if the plumbing problem is outside the house, outdoor PEX tubing is the best possible solution.

PEX is widely popular for the variety of options it provides.

Starting from a 10 feet piece of PEX pipe for small repairs, people have the option to buy rolls of over 500 feet.

Due to the simple installation process, we can use a roll of PEX pipe in its entirety for a house’s entire water supply line.

These pipes have a diameter of ⅜ to 1-inch, making them sturdy enough to use for indoor and outdoor house projects.

Another important feature of PEX pipes is their color-coding.

Anyone can identify them for hot or cold water pipes based on their color.

This color-coding is different from the types of PEX that we will discuss in the next section.

For now, here are the different colors of PEX pipes available:

  • Red PEX: to identify hot water lines.
  • Blue PEX: to identify cold water lines.
  • Gray PEX: Rare PEX pipes that aren’t available at every home improvement store. They can be used for either hot or cold water lines.
  • White PEX: Same as Gray PEX. They can be used for hot or cold water lines, but they aren’t rare PEX pipes.

Types of PEX Pipes

Other than the color-coded property, PEX pipes have three different types.

You can distinguish between them based on their manufacturing process, which determines the PEX pipe installation procedure for later use.

Labeling is simple for PEX when they are stored as rolls in a hardware store.

You will notice the A, B, and C labels on different pipe rolls. Therefore, select the right tubing based on your needs.

PEX-A

This type of PEX is manufactured with peroxide.

Among the three types of tubing, PEX-A is the most flexible option.

It can be used for all kinds of residential water-supply systems, especially during harsh weather temperatures.

PEX-A can expand to great degrees, making it possible to handle freezing water.

While it has many benefits, there is a major drawback.

It’s more expensive than other PEX tubing as a 10-foot PEX-A tube of great quality and manufacturer can cost up to $7.50.

PEX-B

PEX-B is created using the moisture-cure technique, which makes it less flexible than PEX-A pipes.

Unlike other types, PEX-B is inclined to return to its original coiled state because of its stiff nature.

It is less costly than PEX-A and can run somewhere between $2.50 and $5.50 for a 10-foot pipe.

Given the expansion feature and the cost-friendliness, PEX-B is the preferred choice of many house owners.

Among the other types, this one is the best suited for outdoor PEX tubing because it is chlorine-resistant and does not crack under the pressure of freezing water.

We will discuss this in a later section.

PEX-C

PEX-C is very difficult to use because it’s the stiffest of all the PEX pipe options.

This type is manufactured using the irradiation method in which crosslinking is done separately from extrusion.

PEX-C pipes can easily crack under low water temperatures, especially when the water freezes.

They aren’t suitable for handling harsh weather conditions.

However, PEX-C pipes are the best option for short repairs.

When there are no bends or joints required for fixing a pipe, use this type of PEX pipe.

They are the most cost-effective PEX tubes, priced between $1.75 to $3.50 for a 10-foot pipe section.

Benefits of Using PEX Pipes

Benefits of outdoor PEX tubing

Many people do not know that PEX pipes have been around since the 1960s.

Although they are more famous now, the benefits of using PEX pipes have remained almost the same through the years.

Plumbers find it easy to use PEX pipes compared to traditional stiff pipes and share their opinions on the advantages of using them for residential purposes.

Some of the benefits of using these are:

Resistant to Chlorine & Low Temperatures

PEX pipes are resistant to chlorine and corrosion, which is the biggest advantage over standard pipes.

PEX is tested for chlorine resistance during the manufacturing process and is certified only after it passes the highest level.

These pipes are also tolerant of freezing temperatures of water.

PEX outdoor water line is an example of using these pipes for outdoor purposes, as they are less susceptible to outside temperatures.

Easy Installation & DIY-Friendly

When installing PEX pipes, there are no special tools or materials required to complete the installation.

However, it depends on the PEX manufacturer whether you’d need a few extra tools or not.

Some manufacturers use fittings that rotate, making pipe alignment more straightforward.

There is no crimping, gluing, or soldering required.

Some manufacturers do not have that option, so you might need to use cinch clamps, crimp rings, and compression fittings.

Despite that, the installation is still simple and does not require the help of a plumber.

You can DIY the pipe installation without worrying about any mistakes.

Flexible Material

PEX pipes are unlike rigid traditional pipes as they can bend around corners without needing any extra fittings.

Their flexibility makes them ideal for indoor and outdoor PEX tubing for water-supply systems.

However, not all types of PEX are suitable for outdoor use.  

PEX pipes require fewer connection points, thereby reducing the chances of potential leaks.

As there are no joints or elbows to fit the corners, and the material does not have any metal surface, the material cost is drastically reduced.

Are PEX Pipes Suitable for Outdoor Use?

Many theories circulate around the use of outdoor PEX tubing, so it can be hard to figure out whether to use it for your house plumbing or not.

Like every other pipe material, PEX tubes also have their advantages and disadvantages when installing them outside the house.

PEX pipes do not corrode like other metal pipes.

They can expand easily to bear harsh temperatures and even resist chlorine damage.

They are simple to install and do not require the help of a plumber.

However, the UV-resistant factor is where PEX pipes fail.

What Causes PEX to Degrade Under UV Radiation?

Outdoor PEX pipes can degrade under UV light because they absorb the chlorine-blocking antioxidants that protect the pipe.

Without that protection, PEX pipes are vulnerable to damage from chlorinated water.

However, UV radiation is not the only factor for the failure of PEX tubes in an outdoor setting.

Chlorine in the water will damage any PEX pipe over a long period, but due to the exposure to UV and sunlight, the process is accelerated.

If there is a PEX outdoor water line running along with the house, it’s possible to see damage to the pipe within a few months or less.

You can see the same thing happening to PEX pipes when they are exposed to fluorescent lights inside the house.

If PEX is exposed to fluorescent lights for 8 hours straight, it’s the same as 1 minute of sun exposure.

So basically, we can say that the outdoor environment is not the only problem with these pipes.

If we can take the measures to protect the PEX pipes outdoors, they can last longer without degrading under UV light.

How to Protect PEX Pipes for Outdoor Use

Outdoor PEX tubing protection

A few precautions can make PEX pipes more durable for outdoor use.

Here are some methods to protect PEX pipes:

Protect from Direct Light

Protecting PEX pipes from direct UV radiation is a matter of taking precautions.

Look for signs of ‘popcorning’ on the pipe’s surface.

It indicated that the PEX tube is degrading and will eventually fail. Another thing to notice is the white lines along the pipe.

They will look like small scratches and might seem harmless, but they can cause damage to the PEX pipes.

First thing to do is to store PEX pipes away from direct sunlight or fluorescent light.

This is more important before they are installed, so PEX pipe suppliers can store them safely to extend their lifespan, flexibility, and elasticity.  

Protect from Rough Surfaces

We have already discussed that PEX pipes expand or contract based on temperature.

So, if the water is freezing, the pipes will be able to handle it even if they are installed outside.

However, the pipes will move back and forth as they contract or expand, causing damage to the tubes if they are placed on rough surfaces.

Protect from High Temperatures

Outdoor PEX tubing can handle low temperatures of water running through the pipes, but not high temperatures.

If it’s the sunlight or a hot appliance placed near a PEX tube, the damage will be hard to control.

Therefore, keep the PEX pipes away from appliances like water heaters and follow the common building codes for piping.

Keep the PEX pipe 18 inches away from heaters to avoid melting plastic pipes.

Protect from Long-term Damage

Protecting outdoor pipes from sunlight, heat, and rough surfaces can become easier if a person takes measures during PEX pipe installation.

It’s easier to protect these pipes using abrasion clips and pipe insulation.

Another method is to enclose the PEX in a larger pipe to minimize damage for a long time.

By using these tricks, the PEX pipes will be able to withstand external elements for many years to come.

Best Method to Use Outdoor PEX Tubing 

While there are many ways to protect PEX pipes from outside environment damage, a viable option would be to use the direct burial method.

PEX is made up of durable material that can resist chemical damage, and the only problem we are facing by installing PEX outdoors is UV exposure.

By installing the PEX pipes underground, we can reduce the exposure and increase the life expectancy of the pipes.

PEX has the ability to expand when exposed to low temperatures, so even if the underground temperature is freezing, the outdoor PEX tubing won’t crack.

Suitable Type of PEX for Direct Burial Method

We have three types of PEX tubing, and generally, all can work underground.

But some types last longer than others, as their flexibility and expansion features are different.

While talking about the types of PEX, we established that PEX-B should be the first choice for the burial of pipes, but let’s discuss more about all three types and their pros and cons for outdoor underground use.

PEX-A for Underground Use

PEX-A has the highest degree of cross-linking, so the chemical bonds are the strongest.

This feature makes PEX-A the second-best option for underground outdoor PEX tubing after PEX-B.

While the material is non-corrosive and chlorine-resistant, PEX-A has a high chance of contaminating water with chemicals that were used during the manufacturing process.

It makes PEX-A a risky material to use underground.

On the other hand, PEX-A is suitable for burying because it’s flexible and expandable.

It can endure the freezing water temperatures and last longer than many other plumbing materials for outdoor use.

PEX-B for Underground Use

PEX-B tubing is not as flexible as PEX-A.

Still, it makes the best product to be used for outdoor underground plumbing systems.

It has high bursting pressure, so when exposed to extremely cold temperatures, PEX-B can withstand longer than PEX-A or any other PEX pipes.

Another reason to use PEX-B for underground purposes is the affordability factor compared to PEX-A.

You can buy rolls of PEX-B for outdoor PEX tubing that you can bury, and it won’t cost you a fortune.

While the higher bursting pressure makes PEX-B suitable for burying, its manufacturing method may be disadvantageous. PEX-B uses a moisture-cure method which makes the tubing less flexible and more difficult to use.  

Also, if the PEX-B pipes bend while underground, we have to dig up the pipes, replace the damaged section and use additional tubing before placing everything back.

This can be a major headache for people!

PEX-C for Underground Use

PEX-C is not suitable for underground tubing since it is the stiffest of the three types.

If we were to use this for outdoor PEX tubing burial, the pipes would bend and crack upon exposure to freezing temperatures.

The PEX-C option is the cheapest but would require continuous maintenance if buried for outdoor use, ultimately making it the most expensive option.

So, the best thing to do is use PEX-C for short repairs only and go for PEX-A or PEX-B for underground use.

Best PEX Fittings to Use Underground

You know the best type of PEX pipes to use for underground outdoor work, but it will all be meaningless if the right fitting is not installed.

Using the wrong type of fitting can make PEX-A or PEX-B vulnerable to harsh conditions.

Crimp & Clamp Fittings

Clamps and crimps are the two types of PEX fittings commonly used. Although PEX crimps are the best option for pipe installation, they should not be used underground.

PEX crimps are made up of copper, making them susceptible to environmental damage and unsuitable for underground piping.

The main reason to disregard the use of crimps for outdoor PEX tubing is the condition of extreme temperatures.

It is important to consider how cold the temperatures will be underground in different weathers and whether the piping and fittings will be able to withstand it.

If we use copper PEX crimps for underground work, the low temperatures will cause an expansion in the ring, which will result in a leak when the temperature rises.

In contrast to copper crimps, stainless-steel clamp fittings make suitable rings for the direct burial method.

They can resist corrosion and reduce the chances of leaks in changing temperatures.

Sharkbite Fittings

Sharbite fittings are custom rings made by the company for PEX piping.

They are the best choice for outdoor PEX tubing for underground purposes.

The fittings are made of lead-free brass with EPDM O-ring and stainless-steel grab ring.

It’s a push-to-connect fitting that is durable and compatible with a range of pipes.

While the material is ideal for the burial method, the reason we recommend Sharkbite fitting is the silicone tape that wraps the ring.

The company claims that the tape will remain intact to protect the fitting from chemical contamination and ensure their 25-year warranty.

These fittings are an outstanding choice when installing underground PEX tubing because of their quality materials and added protection provided by the silicone tape.

FAQs About Outdoor PEX Pipes

Here are some general questions people ask about outdoor PEX pipes:

What Is the Best Way to Connect PEX to Plumbing Fixtures?

There are many methods to connect PEX to any plumbing fixtures.

If the connection is going to be visible, we can use a copper stub-out connected to the fixture that comes out of the wall.

A compression shut-off valve would work best with the copper stub-out.

If it’s a concealed connection, there is no need to use a joint.

It would be easier to use a PEX pipe directly with the shutoff valve.

If the valves are part of a manifold system, then we can let go of the shutoff valves altogether.

Ask the plumbing inspector to check the water-supply system in the house and give you the best advice for your plumbing fixtures.

Is It Possible to Use PEX Pipes Under Concrete Slabs?

Yes, it is possible to use PEX Pipes with concrete slabs because they are supplied in rolls.

With flexible use and no need for joints or fittings, you can complete PEX pipe installation in a continuous manner.

There is also the option of enclosing it within a concrete slab, which is often used for radiant floor heating.

What If I Make A Mistake During A Fixture?

If you are DIY-ing your way to add PEX pipes to the plumbing system of your house, rest assured that no mistake is permanent.

Use tools like side cutters and rotary tools with a cutoff blade to cut off crimp rings and remove cinch clamps.

Once the ring is removed, the PEX pipe can easily be removed from the fitting, and a new section can be used.

Final Thoughts

Among the three types of PEX tubing, PEX-A and PEX-B serve wonderfully as the outdoor PEX tubing choice for many homeowners.

Even PEX-C can provide value with its usability for short repairs.

PEX pipes had a rough start with the popularity of galvanized steel and traditional copper pipes, but they have gained their footing in the industry.

With decades spent on improvement, PEX is now a preferred product for many residential water supply systems because of its durability and ease of use.

With a lifespan of 40-50 years, PEX pipes are an effective alternative to standard pipes.

With proper installation, they can become an ideal plumbing solution for outdoor use.