PEX Not Allowed: Understanding Where and Where is Pex not Allowed

Are you looking to install PEX pipes for your plumbing or heating system but unsure if it’s permitted in your state? Confused about whether these pipes are actually allowed by industry standards for consumption purposes?

Where is PEX Not Allowed

If you’re in all the boats of confusion regarding PEX pipes being allowed and safe, then you’ve just stumbled into the right place!

Today we are all about PEX pipes being permissible or not, and why or why not, making your pipe purchase surer and more informed.

Without further ado, let’s get right into all there is to know about PEX pipes being allowed or not.

Where Is PEX Not Allowed? In-Depth Discussion

As we just discussed, PEX isn’t really banned anywhere. But there are some areas of work where they aren’t allowed.

This is for a number of reasons. Along with the claims of leaching chemicals, these tubes do not offer antibacterial barriers and are quite porous, which may lead to contamination of the water.

These are some of the areas where PEX isn’t allowed or recommended:

  • Residential Zones
  • Specific Local Codes
  • Industrial Zones
  • Commercial Zones
  • California

1. Residential Zones

Even though the ever-updating technologies have improved the quality and performance of PEX pipes to a great extent, they are still not the most beloved options for residential areas.

Make no mistake- they are perfectly legal in most areas. But only professional installation is allowed as if someone goes all DIY and installs them improperly, things will go wrong in more ways than one.

The number one mistake made by amateurs is installing these pipes directly to a heating device such as a water heater. If the water coming out of the heater is of too high a temperature than these pipes can bear, these pipes can get permanently deformed as they will no longer contract back to their original shape.

Also, upon direct connection to the heater, if you don’t provide the pipes with ample support, you’d see them move a lot due to regular contractions and expansions, causing instability to your system.

Poor joining and attachments of the PEX pipes may also cause leaks and damages, causing bigger issues to rise from the leaks.

Since PEX pipes are softer in comparison to copper, PVC, etc., and are more visually attractive, mice, rats, etc. may have a fun time chewing on them. This isn’t that big of a reason to be alarmed as these pipes are quite sturdy.

But if the rodent infestation is too extensive and they attack the same spots regularly, leaks are bound to arise soon along with causing contamination.

2. Specific Local Codes

While these pipes aren’t strictly banned anywhere, some local area codes do not allow them to be used in the following areas. This is due to ongoing scrutiny of the PPFA (Plastic Pipe and Fitting Association) regarding these pipes’ safety.

Hence, before you decide to settle with PEX pipes, ensure that your local code allows them for your desired purpose.

3. Industrial/Commercial Zones

Commercial and industrial areas don’t allow PEX usually for two reasons- FSR and SDC.

FSR stands for Flame Spread Rating which basically shows how fast flames spread on the material in the event of a fire. SCD represents the Seismic Design Category, which shows the degree of response to seismic activities.

PEX pipes possess a high SCD of almost 50 and an FSR of 25. Hence, they are not allowed to be installed in high-rise commercial or industrial buildings due to these high values.

This is because these values represent the fact that fire would spread rapidly and they will be highly affected by seismic activities. Hence, pipes with an FSR of 25 or higher, and large SCD factors are not allowed.

Another reason for them not being allowed in industrial zones is the fact that PEX is high-density polyethylene, some of these pipes may contain BPA. If exposed to fire in any manner, it would lead to hazardous health complications.

4. California

As discussed earlier, PEX isn’t entirely banned in California since 2010 but the dilemma still remains as California is very strict about the health and well-being of its residents.

While PEX is not a fan favorite, it is definitely allowed but the state will take action against any health risk or damage caused by anything, including PEX pipes.

But if installed, the updated California Plumbing Code requires PEX pipes to be flushed regularly in order to prevent any chances of harmful chemicals getting into the water.

Why Is PEX Banned In California?

PEX was banned in California before 2010, not anymore.

This is because initially, it was suspected that the production of PEX involves harmful chemicals and carcinogens which may leach into the water and cause adverse health issues.

But after rigorous lab tests throughout the country, PEX was finally determined to be safe for use as there was no evidence of leaching. Hence, PEX is no longer banned in California or any other region.

Another factor about the PEX dilemma is the fact that these pipes react with chlorine present in the water. Hence, eventually, scale keeps building up inside the pipes, reducing the internal diameter available for water flow.

This leads to pipes clogging up or getting damaged with time, resulting in them needing repairs/reinstallations.

The battle between California and PEX pipes kept occurring numerous times getting approval and losing it several times until finally it was deemed safe for consumption purposes.

Even though there have been some complaints about water smelling or tasting a little weird coming from PEX pipes, numerous tests have shown these pipes to be safe for potable purposes.

While PEX tubes aren’t the top choice, they sure are approved and are being used in California and all over the United States.

What Are The Requirements To Install It?

PEX pipes can be used anywhere all over the United States for almost all purposes including residential purposes, radiant heating purposes, and industrial/commercial purposes as long as they meet your local codes.

The only factors to keep in mind in case of:

  • Residential Purposes: Get them installed professionally, don’t attach directly to heaters, check for rodent infestations.
  • Radiant Heating: Use pipes with oxygen barriers
  • Commercial/Industrial Purposes: don’t use on high-rise buildings, keep away from excessive heat and open flames.

Besides these, you need to ensure that the PEX pipes of your choice meet the following US standards/requirements at all costs:

  1. ASTM F877 – Conditions for PEX Plastic Cold and Hot Water Distribution Systems.
  2. ASTM F876 – Standard conditions for PEX pipes.

How To Get Permission To Use PEX?

PEX tubes aren’t entirely banned anywhere in the USA anymore but since the ban in California was lifted only a decade ago, you need to ensure if your local code allows you to install PEX tubes.

In order to confirm if PEX is allowed or to get permission to use them in your area, a great option is to get in touch with the corresponding plumbing authority of your community.

You can also reach out to a licensed professional plumber in your local community to seek insight and advice regarding the usage of PEX pipes in your home or office.

Are PEX Tubes Not Allowed In Cold Climates?

There is no rule or law that states that PEX cannot be used in cold climates. In fact, on the contrary, they are superb options for cold regions with freezing climates, if not the best.

This is because, unlike all other tubing options, PEX pipes come with unique elastic features.

Hence, in cold climates, even as freezing as Switzerland for example, your PEX tubing will be perfectly fine. When the water freezes, these pipes will expand flexibly.

Once the water thaws, these pipes will return to their original shape and size without any deformity, cracks, or leaks whatsoever!


As you probably already know where is PEX not allowed? And PEX pipes possess features, durability, and performance unlike no other.

But naturally, all the good things in life come bearing their unique pros and cons, and PEX tubes are no different.

Hence, PEX is still somewhat of a controversial choice and when wanting to choose them for yourself, you are likely to wonder if they are allowed in your state or local zone.

Thus, our purpose today was to guide you through the permissibility of these technological masterpieces so that you can make your choice in full confidence from here on and hope you got it.

Thank you for staying with us

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