PRESS RELEASE

IAPMO to Host Water Demand Calculator® Webinar as California Adopts Voluntary Use of Tool into California Plumbing Code

IAPMO to Host Water Demand Calculator® Webinar as California Adopts Voluntary Use of Tool into California Plumbing Code

Ontario, Calif. — In accordance with the state of California making IAPMO’s Uniform Plumbing Code (UPC®) Appendix M — the Water Demand Calculator® — available for statewide use on a voluntary basis starting today, IAPMO is hosting a webinar that covers the benefits of using the tool to size plumbing in homes and apartment buildings.

Led by IAPMO Vice President of Technical Services and Research Christoph Lohr, P.E., the webinar — which starts at noon PDT today and will be recorded — will provide guidance on using the revolutionary tool, which accurately predicts peak water demand in single-family homes and apartment buildings, reducing the carbon footprint of the structure and saving consumers on both their water and water heating-related energy utility bills for the entire life of the plumbing system. Proper sizing also greatly minimizes the potential threat of bacterial growth within the system, which can lead to such serious health risks as Legionnaires’ disease.

In 2021, the Statewide Utility Codes and Standards Team submitted a Title 24 Petition to adopt Appendix M into the California Plumbing Code during the 2022 Intervening Code Adoption Cycle. The California Water Efficiency Partnership (CalWEP) — a state chapter of the Alliance for Water Efficiency (AWE) of which IAPMO is a member — and 15 member agencies supported the petition.

The Water Demand Calculator reduces water aging, delivers hot water faster, generates significant construction cost savings, reduces the carbon footprint of the structure, and subsequently saves on water- and water heating-related utility bills for the entire life of the plumbing system. Instead of using flow rates and flush volumes from the 1940s, the Water Demand Calculator allows the user to “right-size” the cold and hot water distribution systems in homes and apartment buildings using modern information about flow rates and simultaneous use.

“Today marks an important moment in the history of the Water Demand Calculator as California, the fifth-largest economy in the world, officially implements the use of this 21st-century solution,” Lohr said. “The momentum in adoption of the Water Demand Calculator has been remarkable, with one-fifth of states and a host of other city and regional jurisdictions choosing to adopt this tool in a few short years. We are very grateful to all the volunteers and stakeholders who worked so hard to help make this day possible. IAPMO stands ready to help the California plumbing industry successfully understand how to utilize the Water Demand Calculator for its projects.”

The Water Demand Calculator represents the most impactful innovation in pipe sizing in nearly a century. It is the result of a multiyear effort to develop a new statistically based pipe-sizing method stemming from a need to address profound water safety and wasted water and energy concerns resulting from oversized water supply pipes in homes and buildings.

California is the 10th state to adopt Appendix M into its codes and standards, joining Hawaii, Montana, Nevada, New Jersey, New Mexico, North Dakota, Oregon, Washington and Wisconsin, as well as such major cities as Houston, San Jose, Seattle and Vancouver, British Columbia.

The Water Demand Calculator version 2.2 and user guide, as well as related videos, are available. For specific information about the Water Demand Calculator or to provide feedback, please contact Lohr at mail christoph.lohr@iapmo.org.

Plumbing Industry Gathers at Missouri Capitol to Emphasize Importance of Skilled Professionals in Protecting Health and Water Quality

26 March 2025

Plumbing industry representatives from across the state gathered Tuesday at the state capitol for the first Missouri Pipe Trades Industry Day, a vital opportunity for plumbing professionals to engage directly with lawmakers and policymakers, providing firsthand insights and recommendations on legislation that improves public health, water quality, and economic sustainability. The event, organized by industry leaders and advocates, featured a display of cutting-edge mobile training capabilities, emphasizing the importance of plumbing professionals in safeguarding public health and water quality.

IAPMO Seeks Technical Correlating Committee Members 

25 March 2025

IAPMO® is seeking volunteers to participate on the Technical Correlating Committee (TCC) working toward the correlation of the 2027 editions of the Uniform Swimming Pool, Spa, and Hot Tub Code (USPSHTC) and Uniform Solar, Hydronics and Geothermal Code (USHGC). The deadline to submit an application is May 2. 

South Dakota Updates Plumbing Code to 2024 Uniform Plumbing Code

21 March 2025

South Dakota Gov. Larry Rhoden on March 13 signed into law Senate Bill 25 (SB 25), updating the state’s plumbing code to the 2024 Uniform Plumbing Code (UPC®) from the previously adopted 2015 edition. The adoption was initiated and endorsed by the state’s Plumbing Commission and has the robust support of South Dakota’s plumbing industry.

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