The flexible, polymer pipe known as PEX (cross-linked polyethylene) has gained popularity among home builders in recent years as a cost competitive alternative to traditional rigid piping materials. While PEX water supply systems can offer a significant savings on labor and materials, some hurdles to its widespread use still exist.

Some building professionals have reported challenges in adopting PEX due to the lack of a comprehensive field resource to help them properly design and install the systems. To meet this need, the NAHB Research Center has developed the “Design Guide for Residential PEX Water Supply Plumbing Systems,” a new resource to help increase the adoption and proper use of PEX water supply plumbing systems.

Released at the International Builders' Show in February, the guide provides design concepts and installation guidelines that builders, designers, and contractors need to properly install PEX systems in residential buildings. Homeowners working with a custom builder or serving as a general contractor on a home construction project may also find the guide useful.

Easy-to-follow instructions on installation and joining methods, as well as guidance on code acceptance make the guide a reliable, must-have reference for builders. The guide is also intended as a resource for code inspectors and homeowners wanting to learn more about the performance characteristics and benefits of the technology.

Ease of installation; mechanical connections that eliminate the solder and flame; resistance to scaling, corrosion, and freeze damage; and applications for water conservation and optimal system performance are some benefits covered in the guide. PEX is approved in all the major building codes, but has not yet received local code acceptance in some areas of the country.

The guide was created by the Research Center in partnership with the Plastics Pipe Institute, the Plastic Pipe and Fittings Association, and the Partnership for Advancing Technology in Housing, and is available for free download at