Almost 80% of all water consumption comes from two groups: No. 1, thermoelectric power, and No. 2, irrigation (farming). Public supply, which includes industrial buildings, commercial buildings and residences, accounts for only 10%.

In 2012, the International Association of Plumbing and Mechanical Officials (IAPMO), the University of Cincinnati (U of C), and the American Society of Plumbing Engineers (ASPE) began to work on a new sizing technique 80 years in the making. The main drivers were Dan Cole (IAPMO) and Steve Buchberger (U of C), and later Toju Omaghomi (U of C). As part of this effort, hundreds of thousands of data points were taken and evaluated to determine actual human behavior and plumbing fixture use in residential homes.

In creating Hunter’s Curve, the beauty of what Dr. Roy Hunter did was to take an incredibly complex problem in probability theory and make it simple — so simple, in fact, that all it required was basic arithmetic.

Plumbing engineers and designers have been talking about it for what seems like forever. Plumbing installers have been looking into ways to become more efficient. Plumbing manufacturers have been collecting the data to better size their equipment. And plumbing inspectors and plan reviewers have been acutely aware of the need for change for a long time.