The International Association of Plumbing and Mechanical Officials (IAPMO) has released the 2024 edition of the National Standard Plumbing Code – Illustrated (NSPC).

Plumber at work. <a href=""> Image supplied by</a> on Freepik

Plumber at work. Image supplied by on Freepik

The 2024 NSPC provides the latest information about common materials, fixtures, devices and equipment systems used or installed in plumbing systems. This new edition is printed in illustrated format, with comments and illustrations clearly shown as supplemental information. The illustrations and supplementary notes make it a valuable and easy-to-use training tool.

“The 2024 NSPC reflects the most recent changes in the plumbing industry concerning new products, installation procedures, and public health and safety, consistent with the code’s long tradition of establishing safety requirements for water supply and sanitation systems,” says Tom Pitcherello, NSPC Committee Chairman.

Significant changes to the 2024 NSPC include the following:

  • New provisions for all-gender toilet facilities
  • New provisions for adult changing stations
  • New standards for water closet compartments and urinal partitions
  • Wet venting section completely revised
  • Air admittance valves moved to Chapter 12
  • Appendix G, intended to promote safe and efficient water use in both residential and non-residential buildings, has been updated with revised excerpts from the 2020 Water Efficiency and Sanitation Standard (WE•Stand)
  • IAPMO’s Water Demand Calculator® included as a sizing option in Appendix G
  • New Appendix M, addressing the impact of water temperature on the potential for scalding and Legionella growth
  • New Appendix N, providing requirements for non-sewered sanitation systems
  • New Appendix O, addressing plumbing requirements for indoor horticultural facilities

The first NSPC was published in 1933. It is designed to ensure proper installation of plumbing systems, providing local and state governments, code administration bodies, and the industry with a modern code to protect health and promote safety. In 2017, IAPMO and the Plumbing-Heating-Cooling Contractors—National Association (PHCC) executed an agreement transferring ownership of the NSPC to IAPMO.

To get a look at the new NSPC, visit

Source: IAPMO