HEALTH AND SANITATION 31 using the toilet five times a day, that’ s ten flushes over maybe a ten-hour period. That works out to one flush an hour, and the WDC basically estimates one every 33 minutes.”
“ Large statistics are not intuitive,” Kuchta continues.“ The bigger the project, the more variance.” When asked how adaptable the calculator might be for future shifts in behaviours, he advises,“ We just went through a major change,” referencing COVID and months of a workforce stranded at home. When Hunter was writing his landmark tome, much of the workforce were employed in factories with set break times, supporting Hunter’ s underlying estimates that large projects will have peak demand similar to that of a large football stadium. Today’ s workforce is often hybrid, with staggered arrivals and departures; students in universities curate their class times to their convenience.
“ We just don’ t align our schedules in the way we used to,” Kuchta says.“ Hunter knew he was being too conservative.”
Toward the end of his 1940 paper, Hunter admits that the results will be proven over time.
“ The only complaint against the results of using this table and method that has come to the author’ s attention is that it tends to give larger estimates than have been found necessary for satisfactory service,” Hunter wrote.“ The proof of the adequacy of the proposed method of estimating the demand loads to be expected in buildingwater-supply systems will, in the end, depend on its success in actual trial over a period of years. Fortunately, in this case we have a means of comparison with a similar method that has been given a trial.”
In 2025, tools like the Water Demand Calculator can compare affordable housing, high-rises built for young professionals, student dormitories and vacation housing all with their varied water demands, and provide design that best fits their needs. PA
" Reducing the risk of Legionnaires’ disease in domestic water systems is covered in ASHRAE Guideline 12 and ASHRAE Standard 188, which calls for additional protection for certain occupancies."