6 Reasons Why PEX Plumbing Is Bad for Your Home

Ian Mutuli
Updated on
Ian Mutuli

Ian Mutuli

Founder and Managing Editor of Archute. He is also a graduate architect from The University of Nairobi, Kenya.
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Synthetic materials made from polymers and plastics have, over time, replaced metals, which have long been used to manufacture plumbing materials. PEX piping tubes are among the many popular furnishings that gained popularity in the late 1980s and early 1990s. But why is PEX plumbing bad?

These cross-linked polyethylene PEX plumbing pipes became preferred by homeowners and contractors over CPVC and copper pipes for their affordability, ease of installation, and resistance to harsh weather conditions. However, years later, the shortcomings of PEX plastic pipes are becoming evident.

What Are the Main Types of PEX Pipes?

PEX pipe comes in three varieties: PEX-A, PEX-B, and PEX-C. These types refer to the techniques used to cross-link the polyethylene molecules, which impact the features and properties of PEX pipes.

Types of PEX Pipes

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1. PEX-A

PEX-A pipes are made using the peroxide (Engel) technique of cross-linking. This process usually involves adding a chemical referred to as peroxide throughout the production process, resulting in a high degree of cross-linking.

PEX-A pipes are popular for their exceptional flexibility and shape memory, allowing them to be bent and reshaped without breaking or affecting water flow. Additionally, they exhibit outstanding resistance to stress and cracking.

2. PEX-B

PEX-B pipes are manufactured using the silane (moisture cure) cross-linking technique. During this extrusion, a silane chemical is added to the polyethylene, and cross-linking occurs over time when exposed to moisture.

PEX-B pipes are more flexible and less costly than PEX-A pipes. They also feature a slightly lower level of cross-linking than PEX-A pipes, making them significantly less flexible but still suitable for most plumbing applications.

3. PEX-C

PEX-C pipes are manufactured using the electron beam (radiation) cross-linking technique. This process usually involves exposing the polyethylene material to high-energy electron beams, which induce cross-linking.

PEX-C pipes are both flexible and cost-effective. Compared to PEX-A and PEX-B pipes, they are slightly stiffer because of their lower degree of cross-linking. Nonetheless, they are still suitable for various plumbing projects.

Why is PEX Plumbing Bad?

If you’ve considered using PEX plumbing pipes in your house, you should reconsider. Below are a few reasons PEX plumbing is bad for your home, according to a professional contractor:

Why is PEX Plumbing Bad

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1. Chlorine Issues

Unfortunately, PEX pipes are incompatible and very susceptible to chlorine degradation, like any other plastic pipe. PEX piping has different chemical compatibilities than CPVC piping. Unlike PEX, CPVC pipes have chlorine resistance. However, they are incompatible with other chemicals used in pipe walls, which can cause softening and cracking.

Chlorine degrades PEX pipes and shortens their durability. Most PEX pipe manufacturers use additives to protect PEX pipes from the damaging effects of chlorine. However, the neutralization process consumes these additives over time. This means that the longer the PEX pipe is used, the fewer protective additives are needed.

They are also prone to leaching, and most additives are washed away by water and other liquids that pass through PEX tubing. Leaching and neutralization deplete the number of additives in PEX pipes, exposing them to chlorine degradation.

2. Poor Resistance to Sunlight

PEX piping is also not perfect for outdoor use because of its susceptibility to UV light. Ultraviolet light from the sun acts as a catalyst, stimulating the oxidation process within PEX pipes. Oxidation of PEX pipes consumes the protective chlorine-inhibiting additives, leaving the pipe vulnerable to chlorine degradation.

Poor Resistance to Sunlight

Image Source: hotcore.info

PEX pipes used indoors for hot and cold water should also be protected. A study found that exposing PEX pipes to UV light from fluorescent tubes equals one minute of sun exposure. This explains why PEX pipe manufacturers recommend installing these pipes at least five feet or more away from fluorescent and LED lights. Pipes should also be protected with UV-resistant material.

Most plumbers encountering pinhole-sized leaks from PEX pipes attribute them to UV exposure. However, these leaks and plumbing failures aren’t a direct result of UV light. UV light can’t degrade PEX pipes. Instead, it oxidizes the additives or anti-oxidants in PEX pipes, exposing them to chlorine degradation.

3. It Affects the Quality of Water.

PEX pipes are also known to distort the odor and taste of water. This is a significant issue, especially if you want this pipe to channel cold or hot water for consumption and other indoor uses. While drinking water from PEX plumbing pipes is safe, some PEX pipes can cause an undesirable taste and odor if the water stays longer in the pipe.

Even though the research remains inconclusive, preliminary studies show that PEX pipes negatively affect water quality. The research team found that contaminants like gasoline, pesticides, oil, and benzene can penetrate PEX pipes more easily than other piping types. PEX pipes, including those that have passed safety tests, also contain harmless contaminants that affect water’s taste and smell.

4. Vulnerability to Rodents

Vulnerability to rodent attack is another disappointing fact about plastic pipes, including PEX pipes. Unlike metal pipes made from copper and other metals, rodents can easily bite and chew through PEX pipes. Damage from rodents affects the entire water line by causing leaks and contamination.

5. The Complexity of Installation and Compatibility Issues

PEX installation requires fittings and connections to join parts of the pipe together. Different types of fittings require specific tools and techniques for proper installation. Due to their complexity, plumbing systems are more prone to errors and leaks during installation.

why is pex plumbing bad

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Poor installation or low-quality fittings can make the issue even worse. Besides, the need for fittings and connections adds complexity to the installation process, which increases the possibility of errors and issues.

On the other hand, compatibility problems between PEX pipes and the existing plumbing system might occur during a retrofit or upgrade. PEX plumbing systems usually require special fittings designed for PEX pipes. There will be more potential points of failure in the plumbing system if the existing plumbing system has incompatible fittings or connections.

6. Limited Availability of Repair Materials

Finding suitable replacement parts for PEX plumbing may be more challenging than traditional materials like copper in case of a plumbing issue or repair. While PEX fittings and connections are widely available, specific components or specialized repairs may require contacting the original manufacturer or searching for specific suppliers, which can be time-consuming and costly.

Unlike copper pipes that can be easily soldered or modified, repairing or modifying PEX plumbing systems can be more challenging. PEX pipes require specialized tools and techniques for repairs or alterations. In some cases, pipe sections may need to be cut out and replaced entirely, leading to more extensive and costly repairs than traditional plumbing materials.

How to Avoid PEX Water Quality Issues

Here are some recommended preventive measures you can take to avoid PEX water quality issues and ensure your water supply is safe and clean:

Avoiding PEX Water Quality Issues

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1. Choose High-Quality PEX Products.

Choose PEX pipes and fittings that are certified and meet industry standards. Look for manufacturers with good reputations prioritizing quality control and following strict manufacturing processes.

Moreover, ensure the PEX piping materials have been certified and authorized for use in drinking water applications by independent testing and certification organizations like the Water Quality Association (WQA) or NSF International.

2. Flush the System Before Use.

It is important to flush the system thoroughly before using the PEX plumbing system for the first time or after major changes or repairs. Let the water run from all faucets and fixtures for a few minutes to remove sediment or debris.

3. Avoid Excessive Heat Exposure.

PEX pipes tend to release chemicals at high temperatures. According to manufacturer guidelines and local plumbing codes, set the water heater temperature safely and appropriately. Avoid using an excessively hot water supply that could compromise the pipe’s integrity.

Additionally, regularly monitor the water temperature at different faucets throughout the house. Excessive hot water temperatures can accelerate the leaching of chemicals. Therefore, ensure the temperature doesn’t exceed the safe ranges for comfort and water quality.

4. Periodic Water Testing

Consider conducting regular water testing to assess the safety and quality of the water supply. By testing, you can identify any possible contaminants or changes in water composition. You can contact a certified laboratory to do a comprehensive water analysis.

5. Maintain Proper Plumbing Hygiene.

Regularly clean fixtures, taps, and water sources to maintain good plumbing hygiene. This will prevent the buildup of bacteria, biofilm, and other contaminants that can affect water quality. We recommend following the manufacturer’s guidelines for cleaning and maintenance.

6. Install Point-of-Use Filtration Systems.

Install point-of-use filtration systems, like reverse osmosis or activated carbon filters, at specific faucets or for the whole house. These systems can help enhance water quality by filtering impurities and contaminants.

7. Consult a Plumbing Professional

If you need help maintaining a PEX plumbing system or have concerns about your water quality, we recommend consulting a professional plumber with experience in PEX installations. They can offer guidance, perform inspections, and handle any specific concerns you may have.

PEX Plumbing Alternatives

Before installing PEX pipes in your home’s construction, you should consider the following alternatives:

PEX Plumbing Alternatives Pipe wall

Image Source: simplex.ca

1. Copper Pipes

That copper pipes have stood the test of time doesn’t make them a better alternative. While they are an excellent plumbing option, copper plumbing pipes should be replaced frequently. They are also affected by weather changes and are very costly.

2. PVC Pipes

PVC, or polyvinyl chloride, pipes are popular and capitalize on the disadvantages of PEX pipes, especially for household water supply lines. PVC pipes are long-lasting and safe for outdoor use. They’re also recyclable, making them environmentally friendly.

3. CPVC Pipes

Chlorinated polyvinyl chloride pipes differ slightly from PVC because they contain chlorinated PVC resin. This makes CPVC pipes more resistant to weather changes than PVC. However, they are a costly option.

Endnote: Why is PEX Plumbing Bad?

Even though PEX piping remains a popular option for homeowners, probably because of its affordability and easy installation, it has its downsides. Generally, choosing the best plumbing system for your home or other construction isn’t as simple as most people perceive. Consider the pipes’ safety profile, weather resistance, price, and suitability for outdoor and indoor use. These disadvantages of PEX piping should guide your plumbing choices.

Frequently Asked Questions: Why is PEX Plumbing Bad?

1. Why Don’t Plumbers Like PEX?

The chlorine in the water carried by PEX pipes usually speeds up the brittle oxidative breakdown of cross-linked polyethylene. This breakdown causes the pipes to leak or explode.

2. What is the Problem with PEX?

Some PEX pipe brands use cheap methods that result in faulty pipes with inconsistent composition. Defective PEX pipes quickly deteriorate and become brittle when exposed to hot chlorinated water, rather than lasting the 50+ years promised by the manufacturer. These pipes will inevitably fail.

3. What is the Disadvantage of PEX Supply Systems?

The main disadvantage of PEX is that it’s uncertain how well or how long it will last. Although PEX pipe is warranted for up to 25 years, it’s not known what could happen to it as the years go on. It’s unclear what water will do to plastic over the next 30 years because the material is so novel.

4. How Long Does PEX Pipe Last?

PEX typically has a lifespan of 50 years or more and is long-lasting. Because it doesn’t expand or contract as much when heated and cooled, PEX piping is also less prone to fracture or break than metal pipes.

5. Is PEX Safe for Drinking Water?

PEX is often regarded as safe for drinking water applications. Since the 1970s, PEX pipes have been commonly used in plumbing systems in both residential and commercial buildings. Even though PEX is usually considered safe for drinking water, we recommend consulting your local plumbing codes and regulations and following any manufacturer recommendations and guidelines for installing and using PEX pipes in your area.

6. Which is Better, PVC or PEX?

The decision between PEX and PVC depends on several factors and the specific requirements of your plumbing system. For instance, PVC pipes are more affordable than PEX pipes. If price is a big concern, PVC can be a more budget-friendly option. Conversely, PEX piping systems are usually easier and quicker to install than PVC ones.

Ian Mutuli

About the author

Ian Mutuli

Founder and Managing Editor of Archute. He is also a graduate architect from The University of Nairobi, Kenya.
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