In 2024, more plumbing products became eligible to earn the WaterSense® label, giving plumbing engineers and designers a variety of options to help their customers save water and reduce their utility costs.
The U.S. Environmental Protection Agency (EPA) launched WaterSense as a partnership and voluntary product labeling program in 2006, with the goal to give consumers and businesses a way to identify plumbing and irrigation products that save water and perform well. WaterSense-labeled products are third party certified to use at least 20 percent less water, save energy, and perform as well as or better than regular models. Since the program launched, WaterSense labeled products have helped save 8.7 trillion gallons of water and $207 billion in water and energy bills. To date, more than 45,000 models of plumbing and irrigation products have earned the label.
As more parts of the country face increasing droughts and water supply issues, the EPA introduced new product specifications and refined its existing labeled product criteria to encourage greater water efficiency. The following updates were shared at IAPMO’s Industry Advisory Forum in September or have been subsequently announced by the program.
REDUCING WASTE FROM REVERSE OSMOSIS SYSTEMS
In 2024, the EPA allowed labeling of in-home water treatment systems, finalizing a specification for point-of-use reverse osmosis (RO) systems. RO systems can effectively remove a wide range of contaminants from drinking water, including lead, PFAS, nitrates, and pesticides. However, during the treatment process, RO systems reject some water that is typically discharged as waste — between 4 and 10 gallons per gallon of treated water in most systems — making these systems more water-intensive than other treatment methods, such as filtration. To encourage manufacturers to design and offer systems that reduce this water waste, the EPA initiated point-of-use RO specification development in 2022.
The EPA decided not to label point-of-entry RO systems in this specification. Although point-of-entry systems are commonly equipped with electric booster pumps or other design elements to improve efficiency, treating the full volume of water needed for all household end uses — including toilet flushing, showering, and clothes washing that do not require treated water — results in a greater amount of reject water that is wasted from the system. In most cases, a point-of-use system is sufficient to fulfill the treatment goals of end users, while limiting the quantity of water waste.
The EPA’s final specification was released in November 2024. To earn the WaterSense label, pointof-use RO systems must have an efficiency rating of 30 percent or greater while rejecting no more than 2.3 gallons per gallon of treated water. The EPA estimates that selecting a WaterSense labeled RO system in place of a traditional RO system could save a typical household more than 3,100 gallons of water and $50 in water and wastewater costs per year.
As with all WaterSense specifications, the EPA included performance criteria for RO systems earning the label. First, the WaterSense specification requires that all claims regarding reduction of contaminants such as arsenic, PFAS, VOCs, and others be verified in accordance with NSF/ANSI 58, the primary U.S. industry standard for point-of-use RO systems.
Second, WaterSense requires testing to ensure RO membrane effectiveness is not negatively impacted by operating more efficiently. This testing addresses some concerns raised during specification development that membranes in high-efficiency systems are more prone to fouling and would require more frequent replacement. The specification references membrane lifespan test methods in ASSE 1086, Performance Requirements for Reverse Osmosis Water Efficiency — Drinking Water, the ANSI standard designed to improve RO system water efficiency, which helped kick-start WaterSense’s efforts.
During specification development, the EPA found that information related to RO system water efficiency and contaminant reduction is not always available to consumers. To help purchasers make informed decisions, WaterSense-labeled RO system packaging and website descriptions must clearly indicate information related to system water use and contaminant reduction for arsenic, lead, hexavalent chromium, trivalent chromium, nitrate/nitrite, and PFAS. The EPA says it plans to coordinate with the NSF Drinking Water Treatment Units technical committee to incorporate similar requirements into NSF/ANSI 58, ensuring that all systems meet information transparency requirements in the future.
In conjunction with the new RO system labeling specification, the EPA published two guides to help educate consumers on the water treatment systems they might purchase for their homes: a guide to help consumers understand water quality issues and identify the best treatment option for their needs, including less water-intensive filtration systems; and a guide to selecting and maintaining an RO system based on contaminant reduction and water efficiency. The RO specification and consumer guides are available for download at www.epa.gov/watersense/point-use-reverse-osmosis-systems.
ENSURING WATER SAVINGS IN DUAL-FLUSH TANK-TYPE TOILETS
In May 2024, the EPA completed its first major revision to one of its product specifications, publishing Version 2.0 of its WaterSense Specification for Tank-Type Toilets. The primary change is that the EPA now requires the full-flush of a dual-flush toilet to be 1.28 gallons per flush (gpf) or less. Under the previous specification, WaterSense-labeled dual-flush toilets were allowed to have a full-flush volume of up to 1.6 gpf. Only the effective flush volume, which was calculated based on the average volumes of two reduced flushes and one full flush, needed to be at or below 1.28 gpf.
The EPA said it reviewed multiple studies and determined that this ratio of reduced to full flushes is not always achieved, even in residential settings where tank-type toilets are more prevalent. Additional studies suggested that even users who intend to use the reduced flush setting can be confused by the activation designs. To ensure WaterSense-labeled toilets save significant amounts of water regardless of the flush chosen, the EPA eliminated the effective flush volume calculation and now requires the full flush of dualflush toilets to meet the same maximum flush volume as single-flush toilets. WaterSense-labeled tanktype toilets of all types must still meet performance requirements, including a waste extraction test.
The Version 2.0 specification for tank-type toilets should take effect on July 1 and is expected to impact approximately 75 percent of existing WaterSense labeled dual-flush toilet models. Single-flush toilets are not impacted by the new specification and do not require retesting. After July 1, the EPA says it plans to designate any dual-flush toilets that do not meet the updated efficiency criteria as delisted. However, delisted models should remain on the WaterSense Product Search Tool until Jan. 1, 2026, to allow time for previously manufactured products to be sold. EPA licensed certifying bodies plan to work with manufacturers to retest toilets and certify new models that meet the updated specification.
FAUCETS GET MORE EFFICIENT
In December 2024, the EPA released draft revisions to its WaterSense specification for private lavatory faucets and faucet accessories to reflect changes in the marketplace for these products. EPA says the primary goal of the proposed Version 2.0 of the specification is to ensure the WaterSense label continues to represent the most efficient models by reducing the maximum flow rate from 1.5 gallons per minute (gpm) to 1.2 gpm when tested at a flowing pressure of 60 psi. Canada and multiple states such as California, New York, Oregon, and Washington have adopted efficiency standards requiring private lavatory faucets to flow at a rate no higher than 1.2 gpm. The marketplace has responded accordingly — according to the EPA, nearly two-thirds of WaterSense-labeled models already operate at 1.2 gpm or less.
The EPA also says it plans to retain its minimum flow rate criteria that require lavatory faucets to maintain a minimum flow rate of 0.8 gpm at 20 psi, the lowest water pressure acceptable under U.S. model plumbing codes. This minimum flow rate is sufficient to perform common tasks for which private lavatory faucets are used, such as face washing and shaving. Reducing faucet flow rates as low as the 0.5 gpm level required by plumbing codes for public lavatory faucets could have unintended consequences within residential settings related to hot water delivery, wastewater flow, or pathogen growth.
The EPA says it considered expanding the scope of its lavatory faucets specification to include other faucet types, namely kitchen faucets. As with private lavatory faucets, numerous states and Canada have adopted efficiency standards requiring kitchen faucets to flow at rates below the current U.S. federal maximum flow rate of 2.2 gpm, and manufacturers now offer more efficient kitchen faucet models. While WaterSense is interested in developing criteria to further encourage the market transformation for water-efficient kitchen faucets, they decided a separate WaterSense specification focused on kitchen faucets would be better suited.
WATERSENSE COVERS MORE THAN PRODUCTS
While WaterSense-labeled products are the most visible part of the program for plumbing professionals, WaterSense also advances water efficiency in the built environment through other aspects of its program. For example, the EPA offers the WaterSense label to new and renovated homes that are at least 30 percent more water-efficient than a typical new construction home. Builders can certify their homes to meet this criterion by installing WaterSense-labeled products and ENERGY STAR-certified appliances, as well as incorporating efficient hot water delivery systems and landscape and irrigation system designs that reduce the amount of water used outdoors. (Learn more about WaterSense labeled homes at www.epa.gov/watersense/homes.)
Water management and efficiency in commercial and institutional facilities are also promoted via a series of WaterSense at Work best management practices, a comprehensive resource that helps facility owners and managers improve water management. The series covers water use monitoring; sanitary fixtures and equipment; commercial kitchen equipment; outdoor water use; mechanical systems; laboratory and medical equipment; and alternative water sources. The best management practices and other tools and resources for commercial and institutional facility managers can be found at www.epa.gov/watersense/commercial-buildings.
WHAT’S NEXT?
As many of us have heard in the mainstream news, there has been some discussion about the potential of rolling back certain government efficiency programs. On February 14, 2025, EPA Administrator Lee Zeldin announced there may be changes to energy efficiency rules. Currently, there is no additional information to report on the status of the WaterSense program, but it’s worth noting that this program has been successful and generally supported by the industry at large. For a summary of the latest WaterSense plumbing product updates and more information about other types of products and program efforts, direct your web browser to www.epa.gov/watersense.
