Pacific Institute Report Recommends IAPMO’s Water Demand Calculator as a Key Strategy for National Water Efficiency

Ontario, California — IAPMO^®, a global team of experts engaging industry and government for a safer built environment, is proud to announce that its Water Demand Calculator^® has been featured as a key recommendation in the Pacific Institute’s new landmark report, “Untapped Potential: An Assessment of Municipal and Industrial Water Efficiency Potential in the United States.”

The first-of-its-kind national assessment finds that improving water efficiency could reduce municipal and industrial water use across the United States by 25-60%, saving billions of gallons each day and significantly lowering infrastructure and energy costs. The Pacific Institute specifically recommends the adoption of IAPMO’s Water Demand Calculator as an essential tool to achieve these savings by right-sizing plumbing systems to reduce structural water waste, lower construction costs, and improve water quality.

The report asserts: “States and municipalities should amend their plumbing codes to require IAPMO’s Water Demand Calculator for estimating peak demand and provide training on its use for inspectors, installers, and design professionals.”

The Pacific Institute is a leading nonpartisan research organization dedicated to advancing water sustainability and resilience through innovative science-based analysis, policy recommendations, and partnerships that promote equitable and efficient water management solutions worldwide.

Christoph Lohr, IAPMO’s vice president of Technical Services and Research, played an integral role in the development of the report as a member of its Advisory Group. His research and several IAPMO publications are cited throughout the study, underscoring the organization’s leadership in advancing practical, evidence-based water efficiency solutions.

“It’s an honor to see the Pacific Institute recognize the transformative potential of the Water Demand Calculator,” Lohr said. “By rethinking how we size plumbing systems, we’re not only saving water but also cutting construction costs, improving energy efficiency, and enhancing public health through better water quality. This report reinforces what we at IAPMO have long believed — smart plumbing design is foundational to sustainable water management.”

Developed by IAPMO through years of technical research and collaboration with industry partners, the Water Demand Calculator enables designers and engineers to more accurately estimate peak water demand in residential and multifamily buildings. By aligning plumbing system design with actual water use patterns rather than outdated assumptions, the tool helps reduce pipe sizing, minimize stagnation, and improve system efficiency and performance.

Read more about the Water Demand Calculator.

The Pacific Institute’s Untapped Potential report serves as a powerful call to action for policymakers, utilities, and industry professionals to adopt proven, cost-effective technologies like the Water Demand Calculator to help strengthen the nation’s water resilience. Among its key findings are:

• Existing technologies and practices could save 14.0 to 34.1 million acre-feet per year, equivalent to 12.5 to 30.4 billion gallons each day. This represents a 25-60% reduction in municipal and industrial water use.  
• Households offer major water savings potential both indoors and outdoors, while businesses and institutions present smaller yet still significant savings opportunities. Fixing leaks in water delivery systems represents a large and cost-effective, but underfunded, opportunity.
• Water efficiency saves water and energy, cuts utility costs, and protects the environment, but it is often overlooked in water supply planning and underfunded compared to new supply projects.
• Water savings are possible in every state and across sectors. The assessment offers decision-makers insights into the diversity of water savings opportunities available. 

“By reducing leaks and adopting proven technologies and practices, we can save tens of millions of acre-feet of water each year — enough to dramatically reduce pressure on lakes, rivers, and aquifers while also supporting a vibrant economy and resilient communities,” said Heather Cooley, chief research and program officer at the Pacific Institute. “We’re excited to see this research helping to reframe efficiency as one of the most powerful and practical tools for building a sustainable water future.”

The full report is available online, and the Pacific Institute will host a webinar to discuss its findings on Dec. 4.