Modern plumbers favor PEX (cross-linked polyethylene) over traditional materials because it is highly flexible, cost-effective, and faster to install. It resists corrosion, scale buildup, and bursting during freezing temperatures.
PEX pipe is more resistant to bursting in freezing conditions than metal piping. Because it's flexible, PEX tubing expands rather than splitting, minimizing costly repairs. A long product lifespan reduces cost associated with it, increases customer satisfaction and lessens waste.
While PEX (cross-linked polyethylene) pipes are flexible, cost-effective, and resistant to freezing, they have notable disadvantages. Key drawbacks include degradation from UV sunlight, susceptibility to rodent damage, chemical leaching risks, flow restrictions from inner fittings, and poor fire resistance.
In 2021 the pipe was discontinued and is no longer manufactured the same way.
It has become expensive, can still corrode based on pH levels of water, and in cold climates, frozen water can cause copper pipes to burst. PEX installs quickly, which significantly reduces labor costs. It is easy to install due to its flexibility, and has fewer fittings, which can reduce the chance for leaks.
Leaks and Fittings Issues
PEX plumbing uses fittings and connectors that are typically made of plastic or metal. Over time, these fittings can loosen, leading to leaks. Problems can arise with crimp rings, as improper use of a crimping tool can weaken the joints.
The "135-degree rule" in plumbing states that the total (aggregate) horizontal change in direction for a drainage pipe—specifically trap arms—cannot exceed 135 degrees between the P-trap and the vent. Exceeding 135 degrees (such as using three 45-degree bends or a 90 and two 45s) requires a cleanout because sharp turns hinder flow and cause clogs.
While PEX is highly flexible, affordable, and easy to install, it can degrade under UV light and is susceptible to rodent damage. Depending on your priorities—longevity, water purity, or structural rigidity—the primary alternatives listed below outperform PEX in specific applications.
Many homeowners choose PEX because it promises quick installation and lower costs. However, not everything about PEX plumbing is as good as it seems. Over time, several issues have emerged that can affect water quality, durability, and even your home's safety.
Yes, mice and other rodents can absolutely chew through PEX pipe. Because PEX is a flexible plastic, it is relatively soft compared to metal and is highly susceptible to damage from the continuously growing teeth of mice and rats.
Emerging research suggests that PEX (cross-linked polyethylene) pipes can shed microplastics and leach chemicals into drinking water. However, the extent of this contamination and its health impacts remain a subject of ongoing debate between consumer safety groups and the plastic piping industry.
The "purple stuff" plumbers use is purple primer. It is a chemical solvent used to clean and soften the surface of PVC and CPVC pipes before applying pipe glue (solvent cement). The bright purple dye provides visible proof to building inspectors that the required primer was used.
PEX (cross-linked polyethylene) plumbing typically lasts between 40 and 50 years. Manufacturers often provide warranties of 25 years, but when properly installed and maintained within standard water pressure and temperature limits, the tubing itself often exceeds a half-century of use.
PEX is cheaper than copper, both in terms of material and labor costs. The cost of PEX vs copper is particularly important for large-scale projects, such as commercial repiping, where budget constraints are a key factor. PEX is also easier to install.
Vinegar acts as a highly effective, natural cleaning and polishing agent for copper. The acetic acid in vinegar reacts with copper oxide (the dark or green tarnish) to dissolve it, restoring the metal’s bright, shiny appearance.
Pex and copper pipes each have their advantages, but Pex often edges out copper in terms of flexibility and ease of installation. Pex is resistant to corrosion, less likely to freeze and burst, and generally more cost- effective. However, copper is highly durable and has a longer track record for reliability.
PEX pipe is more durable than rigid pipe in cold weather but is still susceptible to burst in extreme conditions. To ensure your PEX lasts through extreme weather, insulate your pipes or use our other tips to keep your pipes at an appropriate temperature.
If you bend or expand a PEX pipe and it easily returns to its original shape (and no kinks), there is a high probability that it is a PEX A pipe. On the other hand, if you expand or stretch a PEX pipe and it can hardly regain its original shape, there is a high probability that it is a PEX B tubing.
Yes, PEX pipes can sometimes make water taste or smell "plasticky" or stale, especially if the pipes are brand new or if water sits stagnant in them for a long time. While these compounds leach in very low and safe amounts, they can alter the water's flavor.
PEX Failures
The pipe can fail when exposed to chlorine within the water, or over exposure to sunlight before installation. In addition, PEX pipe has also been found to be permeable when exposed to some solutions, including oxygen and some petroleum products, and can leach toxic chemicals from the pipe material.
Some homeowners may mention how PVC can last around 100 years, and PEX might last half of that. PEX often lasts around 50 years. However, PEX is more durable and has more flexibility than PVC and CPVC. Also, because PEX is made from cross-linked polyethylene, it won't corrode.
We only use PEX-B, the most widely used and trusted PEX by far. It's the workhorse of the PEX world. It's what everyone uses, and it's just plain reliable. So, expansion fittings, they're kind of like a niche thing, not really worth the hassle or the extra cost unless you have a specific reason to use them.
To protect your plumbing and the environment, you should never put fats, starches, harsh chemicals, or solid waste down your drains.
a waste pipe must be layed so it has a fall of 1 in 4 (mcguires rule).
Here are the most common plumbing code violations you might not even realize you have—and why they matter.