Written by IAPMO 8:39 pm IAPMO News, Plumbing News, Plumbing News, Sustainable Codes

IAPMO’s Water Demand Calculator™ Version 2.2 Available for Download

Ontario, Calif. — The International Association of Plumbing and Mechanical Officials (IAPMO®) is excited to announce that the Water Demand Calculator™ version 2.2 is now available for download.

While the basic template of version 2.1 of the calculator remains intact, version 2.2 includes several new features. First, version 2.2 implements a new algorithm called the method of convolution to replace exhaustive enumeration. The new algorithm is faster and has a smoother transition to the other methods of computation. This new computation method assures accurate predictions of peak indoor water demand.

A second new feature of the Water Demand Calculator version 2.2 is the enhanced display showing the method of computation. After running the Water Demand Calculator, a new box in the computed results column shows the exact algorithm used in the calculation.

A third new feature of version 2.2 is that the results of the peak flow calculation are now downloaded in a Microsoft Excel spreadsheet rather than a text file. The spreadsheet displays all the results and the list of fixtures and fixture counts entered into the calculation. In addition, an updated user guide is also available for version 2.2.

“The Water Demand Calculator has become more robust while remaining fast, accurate and user-friendly,” said Dan Cole, IAPMO’s senior director of Technical Services. “Increasing the accuracy in predicting peak water demand for single- and multifamily dwellings will lead to reductions in pipe sizing accompanied by additional cost savings.”

The Water Demand Calculator version 2.2 and user guide may be downloaded HERE. For specific information about the Water Demand Calculator or to provide feedback, please contact Dan Cole at dan.cole@iapmo.org.


IAPMO develops and publishes the Uniform Plumbing Code®, the most widely recognized code of practice used by the plumbing industry worldwide; Uniform Mechanical Code®; Uniform Swimming Pool, Spa and Hot Tub Code®; and Uniform Solar Energy, Hydronics and Geothermal Code — the only plumbing, mechanical, solar energy and swimming pool codes designated by ANSI as American National Standards — and the Water Efficiency Standard (WE-Stand)™. IAPMO works with government, contractors, labor force, and manufacturers to produce product standards, technical manuals, personnel certification/educational programs and additional resources in order to meet the ever-evolving demands of the industry in protecting public health and safety.

Last modified: June 15, 2023