Design Guide. Residential PEX Water Supply Plumbing Systems

This Design Guide provides the information and resources necessary to design and install cross-linked polyethylene (PEX) water supply systems in residential buildings. It includes comprehensive design concepts and installation guidelines to increase the acceptance and proper use of PEX. This document is targeted to meet the needs of home builders, designers, and trade contractors. Its purpose is to introduce potential users and to enable current users to optimize their PEX plumbing and minimize system costs. In addition, it will allow code inspectors and homeowners to become familiar with the applications, performance characteristics, and benefits of PEX water supply systems.


This PEX Design Guide can be used by anyone considering the installation of PEX piping for a residential plumbing system. It can be used by the novice as an introduction to PEX piping or by the experienced plumber to optimize his/her approach. Building code officials can use this Guide as a consolidated source of information on the application of PEX piping in residential buildings. Builders can use this guide to learn about the advantages, installation issues, and expected performance of PEX plumbing systems for discussions with sales staff and homeowners.