Significant changes to length of hot water piping to fixtures in the 2021 International Residential Code

An addition to Section P2905.3 (Length of Hot Water Piping to Fixtures) of the 2021 International Residential Code states that the code now limits the length of hot water piping serving fixtures.

A new section limits the hot water supply line length to 100 feet measured from the source of hot water to the fixtures that require hot water. This provision is similar to existing language in International Plumbing Code (IPC) Section 607.2, except the IPC limits the length to not greater than 50 feet. Hot water supply lines greater than 100 feet wastewater (proportional to pipe size) while occupants wait for hot water to reach fixtures for bathing, washing and culinary purposes. Even when hot water supply lines are insulated, the hot water remaining in the lines between demand periods cools down. Limiting the length and consequent volume of heated water in the supply lines reduces the amount of wasted water and occupant waiting time.

Read the full significant change.

The 2021 Significant Changes guides are available for the International Building, Fire, Residential, Energy Conservation, Plumbing, Mechanical and Fuel Gas Codes. This valuable series can help any code user save time by zeroing in on the most critical changes in the 2021 International Codes. The Code Council’s technical experts provide summaries, analysis and graphics for these changes making them clear and easy to understand. Each edition provides a comprehensive analysis of significant changes since the 2018 edition, offering key insights into its contents and implications. Each change analysis features the affected code sections and identifies the change with strikethroughs and underlines to show modifications to the existing language. Each change is accompanied by a quick summary, detailed illustrations, and a discussion of its significance, which brings the technical jargon of the code to life in a real-world setting.

Significant Changes to the International Residential Code, 2021 Edition, is available in the ICC Store or through Digital Codes Premium.