Driven by landmark legislation, water safety and sustainability concerns, innovative new products and materials, enhanced research and testing capabilities, continuous development of codes and standards and an unprecedented level of professional collaboration, the plumbing industry has experienced more changes in the last half-century than at any other time in history.

International Association of Plumbing and Mechanical Officials (IAPMO) Executive Vice President of Continuous Improvement Programs Pete DeMarco and IAPMO Senior Vice President of Codes and Standards Hugo Aguilar share what they believe are some of the major milestones encountered along the way that have made the plumbing industry what it is today, as viewed from the perspective of their organization.

A Glance Back at the Past

Early 1970s: Ceramic and anti-scalding valves. The industry standard, ceramic valves were created for their ability to produce a watertight seal in plumbing products while resisting wear and the frequent need for replacement parts associated with valves using elastomeric or other seals. 

Product standards were first published in 1973 for anti-scalding valves that prevent a sudden change in shower water temperature caused by a decrease in hot- or cold-water pressure when, for example, a toilet is flushed or a washing machine is turned on, to prevent scalding and injuries such as slipping and falling, particularly among older adults and children.

1974: Safe Drinking Water Act (SDWA). Passage of the SDWA, according to DeMarco, has had a “huge impact” in that it authorized the U.S. Environmental Protection Agency (EPA), for the first time, to establish and enforce limits on levels of contaminants in drinking water. At present, more than 90 different contaminants are regulated by the EPA, with 92% of the nation’s water supplies in compliance with established limits.

1980s-Present: Plumbing standards and certification programs. Although the ASME 1112 Committee was established in 1955 to standardize plumbing materials and equipment, it wasn’t until nearly a quarter century later that these standards became widespread as they were gradually adopted into local plumbing codes. 

As a result, it became necessary to develop independent laboratory testing capabilities and rigorous third-party certification programs for the manufacturing community to help protect public health and safety and keep substandard products out of U.S. and Canadian markets.

1980s: CPVC and PEX. Offering greater durability and heat resistance than PVC, CPVC was added to the Uniform Plumbing Code (UPC) in 1982. Introduced later during that same decade, PEX has properties similar to those of CPVC but provides a more flexible alternative that has made it the most commonly used pipe material for new home construction and replacement piping today.

1987: Canada-United States Free Trade Agreement (CUSFTA). Following approval of the CUSFTA, a major effort was made to harmonize plumbing standards between the United States and Canada to eliminate confusion and promote free- and fair-trade practices. Although other agreements have since superseded CUSFTA, this process of harmonization continues today with binational or single standards serving both countries developed jointly by the Canadian Standards Association and IAPMO.

1991: Lead and Copper Rule (LCR). Published by the EPA on behalf of the SDWA, the LCR was “a big deal for the industry,” Aguilar says, because it required the development of new plumbing products and materials to reduce the amount of lead and copper in drinking water. Since 1991, the LCR has been revised multiple times to introduce more stringent requirements; the most recent revision was in 2021.

1992: Energy Policy Act (EPAct92). The EPAct92 established minimum water efficiency standards for new plumbing fixtures such as showerheads, faucets, urinals and toilets in the United States. Performance of new products meeting these standards, which in the case of toilets required roughly a 50% reduction to 1.6 gpm, was initially disappointing. However, improvements in quality since then have led to widespread consumer acceptance and a precipitous decline in water use nationwide.

1993: Leadership in Energy Efficiency and Environment Design (LEED) program. LEED was created by the U.S. Green Building Council, a nonprofit organization based in Washington, D.C. It is the most widely used system for rating green buildings globally and is based on third-party verification of a building’s design, construction and operation in categories involving environmental sustainability and energy efficiency.

1999: Americans with Disabilities Act (ADA). Characterized by DeMarco as a “profound piece of legislation,” the ADA initially required manufacturers to redesign bathroom fixtures, including lavatories, toilets and urinals specifically for people with disabilities. Over time, this led to the development of universal designs for use by disabled and nondisabled individuals that are preferred for use in buildings today.

2000: World Plumbing Council (WPC). An international organization headquartered in Switzerland, the WPC is dedicated to the growth and development of the world’s plumbing industries by improving their ability to deal with public health and the environment. 

With members in more than 30 countries, the WPC helped establish March 11 as World Plumbing Day and sponsors the triennial World Plumbing Conference, the next installment of which will be held in Shanghai, China, later this year.

2003: American National Standards Institute (ANSI) accreditation. Recognition of IAPMO’s uniform codes by ANSI starting in 2003 gave greater confidence to the codes’ users that they were developed using a highly reputable and widely accepted process. This process requires an open, consensus-based approach, providing all potential stakeholders — including the public — with reasonable opportunities to participate.

2003: Maximum Performance (MaP) scores. MaP scores were developed by a group of 22 organizations in the United States and Canada to objectively determine how much solid waste a toilet can dispose of in a single flush. While testing is voluntary, more than 4,500 tank-type toilets made by more than 160 manufacturers have been tested. MaP scores are posted online for consumers to consult at no charge to assist them when purchasing a toilet. 

2006: WaterSense. The EPA’s 2006 voluntary WaterSense Certification Program took EPAct92 one step further by requiring an additional 20% improvement in product water use efficiency. According to DeMarco, who co-chaired a committee advocating its adoption, WaterSense standards have become so widely accepted they’ve “even become the law of the land in some states and counties around the country.”

2014: Emerging Water Technology Symposium (EWTS). Co-convened annually by IAPMO, the American Society of Plumbing Engineers, the Alliance for Water Efficiency and Plumbing Manufacturers International, the EWTS provides an opportunity for attendees to learn about and discuss emerging technologies that can benefit water safety and sustainability with leading experts from around the world. 

DeMarco was the technical facilitator for the first six of these events that he says “position the United States at the forefront of these issues” in a forum that increasingly involves international participation.

2015: Pathogen control standards. Aguilar notes that guidelines for preventing the growth of Legionella first appeared during the late 1990s, with the 2015 ASHRAE Standard 188, Legionellosis: Risk Management for Building Water Systems, becoming one of the most prominent. 

Awareness of the need to control other potential contaminants, he adds, has since led to the process of developing ASHRAE Standard 514, Risk Management for Building Water Systems: Physical, Chemical and Microbial Hazards, “to address the prevention of injury and disease from Legionella as well as other waterborne pathogens, chemicals and physical hazards.”

2017: Water Efficiency and Sanitation Standard (WE.Stand). Introduced in 2017,  Aguilar maintains that IAPMO’s WE.Stand is “revolutionary” in that it is the “first industry standard focused exclusively on achieving safer and efficient water use in residential and nonresidential buildings.” Published using ANSI-accredited development procedures, the 2020 edition encompasses everything from water-efficient plumbing fixtures and appliances to composting toilets and rainwater catchment systems.

2018: Water treatment standards. In response to high-profile media reports of lead and other contaminants found in municipal drinking water supplies, point-of-entry and point-of-use water filtration systems burgeoned in popularity. To ensure safer and more reliable performance, standards for these systems were established by the American Society of Sanitary Engineers International, NSF International and IAPMO starting in 2018 and later referenced in the 2021 UPC. 

2021: Water Demand Calculator (WDC). IAPMO developed the WDC to replace the nearly 90-year-old Hunter’s Curve previously used to calculate pipe requirements that Aguilar says were “grossly oversized” based on today’s flow rates. “With WDC,” he explains, “all you have to do is enter the number of fixtures you have and it gives you the flow rate you need to right-size your pipe requirements.”

Fast-Forward to the Future

Looking ahead, many of the problems of the past will undoubtedly persist, while others, such as those precipitated by climate change, for example, will certainly emerge. Despite this, Aguilar believes the experience gained and the lessons learned from the last half-century have made the industry “more resilient and better prepared” to confront the challenges of tomorrow. 

DeMarco agrees: “We’re better off because the plumbing industry in total — including manufacturers, utilities and certainly the organizations who’ve worked so hard behind the scenes to apply the right standards and solutions — have helped ensure that when we do encounter new problems, they’ll be worked on with the same rigor as the others and with much better knowledge.”

Which is a fitting tribute to all those who’ve participated in the progress of the plumbing industry for the last 50 years. 

Award-winning writer Stephen Webb has regularly contributed to IAPMO’s flagship publication, Official, since 2007. He received his master’s in communications from California State University, Fullerton, where he taught for several years before founding his own marketing communications company. With personal experience in construction, Webb especially likes working with professionals committed to advancing the industry’s standards of excellence.