We earn a commission when you buy through our links at no extra cost to you

Why Is PEX Banned in California

For a long time, copper has been regarded as safe, and everyone is familiar with its installation. However, it is expensive, prone to corrosion, and even bursting during cold weather. PEX has risen to become one of the top contenders in plumbing industry. PEX is a cross-linked polyethylene developed in Germany in the 1960’s. It was later introduced in the United States in the 1980s, where it gained popularity as an excellent alternative in plumbing systems. Despite its numerous advantages such as flexibility, versatility, affordability, and ease of use, some states like California are still concerned about its safety.

PEX Battle Timeline

The battle to legalize PEX use in California has been ongoing for quite some time now. PEX was banned in California until 2010, but it is still illegal in some local codes. For over 30 years, PEX has been used in the United States. It has passed some of the stringent safety and durability tests set by multiple national testing laboratories.

The Plastic Pipe and Fittings Association and California Building Standards Commission have had a back and forth court cases regarding the safety of PEX. The California state has always been concerned about the quality of water from PEX tubing. In 2004, the California Court of Appeal issued a directive for the PEX pipes used in buildings and plumbing systems to be subjected to environmental review. This decision was later finalized by the court on December 15, 2004.

A breakthrough came on January 22, 2009, when Building Standards approved PEX. On January 12, 2010, the court enjoined its use. Check with your local building codes to know if it is approved within your jurisdiction.

Why PEX Was Banned in California

PEX is considered safe and even accepted by various building codes. However, there is some vulnerability due to the systems’ materials and components. PEX was banned in California due to the following concerns.

Quality of Drinking Water

Even with the various water quality tests, some research shows that some PEX piping brands affect water quality. It shows that the products contain material contaminants that may affect the taste and smell of water. As a response to address this issue, the contractors are required to flush the system after installation.


Certain products like oxygen and petroleum products are likely to promote the permeability of the tubing. In an underground installation where pesticides are present, the products may penetrate through the pipe and contaminate the water supply. Besides, oxygen in radiant floor heating systems may also cause heating element corrosion.

Ultraviolet Light

Exposure to ultraviolet light can cause PEX piping to be brittle, just like any other plastic pipe. Studies show that overexposure to sunlight significantly reduces chlorine resistance. PEX is not suitable for exterior settings.

Read : Best water hammer arrestor

Chemical Leaching

Another downside of the PEX system is possible chemical leaching. Its chemical composition is also causing concerns because the toxic chemicals like MTBE, bisphenol may leach and contaminate the water.

Final Thoughts

PEX was banned in California due to some concerns about toxic materials leaking through the pipe and into water. Through various national laboratory tests, PEX has proven to be completely safe and durable. It is now legal in California and even included in principal plumbing codes.