Written by Anish Desai 10:42 pm IAPMO R&T - WaterSense, Product Certification, Product Testing & Certification

Examining the WaterSense Certification for Flushing Urinals

Recognizing that urinals in commercial and institutional settings represent a significant source of excessive water use, the Energy Policy Act of 1992 set a maximum flush volume for all urinals manufactured in the United States after Jan. 1, 1994, of 1.0 gallon per flush (gpf). By converting inefficient urinals to this standard, the typical office building could conserve up to 26,000 gallons of water or more per year. Of the 12 million urinals currently in use in the United States, however, as many as 7.8 million, or 65 percent, are older units that exceed the maximum volume per flush set by federal standards by as much as 3.0 gpf.

Since the 1994 standards were established, manufacturers have continued to reduce water requirements for urinals to the extent that newer, high-efficiency models use less than 0.5 gpf, which is now the qualifying benchmark for WaterSense-certified urinals. Urinals meeting this requirement must also comply with other flushing urinal standards and be independently certified for flushing effectiveness and having fully functioning drain traps.

Exchanging just one 1.5 gpf urinal with a 0.5 gpf WaterSense-certified model could conserve more than 4,600 gallons of water annually. Doing so with every older, inefficient urinal in every office building and other institution in America could save nearly 35 billion gallons of water a year or enough to fill 720,000 bathtubs.

Certification Criteria
The water-efficiency component of the specification establishes a maximum average flush volume of 0.5 gpf (1.9 Lpf) when tested in accordance with ASME A112.19.2/Canadian Standards Association (CSA) B45.1, ASME A112.19.3/CSA B45.4, or IAPMO Z124.9, as applicable. This value represents a 50 percent reduction from the current 1.0 gpf standard and is consistent with WaterSense’s stated goal of increasing product water efficiency by at least 20 percent.

For flushing devices, there are several additional requirements in the specification that go beyond the requirements of ASSE 1037 (for pressurized flushing devices) and ASME A112.19.2/CSA B45.1 (for flush tank [gravity-type] flushing devices). In addition to complying with all aspects of the applicable standards, three additional requirements apply to all flushing devices:
● The non-hold-open design requirement is designed to eliminate the ability to increase the device’s flush volume by holding the actuator open. This requirement has been revised from what was proposed in the draft specification to apply only to the flushing device’s primary actuator. This change primarily affects sensor-activated flushing devices that incorporate manual actuators or overrides for emergency or maintenance use. These secondary manual actuators are not intended to be used as the main actuator for these flushing devices, and therefore typically would not meet this requirement. WaterSense recognizes that requiring secondary actuators to comply with this requirement could be cost prohibitive and design restrictive and would not significantly contribute to water savings.

● The flushing device must not be adjustable as to its rated flush volume beyond a specified tolerance of ± 0.1 gpf (0.4 Lpf). The non-adjustability requirement ensures that the product’s water consumption in the field can be maintained. This requirement also has been revised from the draft specification to include a specific tolerance allowance. This change reflects the frequent need for field adjusting of flushing devices to account for site-specific differences in water pressures, inherent fluctuations or variances in flushing performance of individual flushing devices and fine-tuning different flushing device and fixture combinations to achieve maximum performance. Pressurized flushing devices may have a flush volume adjustment if it does not allow the rated flush volume to vary by more than ± 0.1 gpf from the device’s manufacturer-specified flush volume (rated flush volume). For gravity tank-type flushing devices, the maximum volume of water discharged by the tank when the tank trim is adjusted to its maximum water use setting cannot vary by more than ± 0.1 gpf from the device’s rated flush volume. These changes simply acknowledge the inherent variability of all flushing devices when installed in the field.

● The flushing device must be designed such that replaceable or maintainable parts are not intended to be interchangeable with parts that would cause the device to exceed its rated flush volume. WaterSense is maintaining the requirement that the flushing devices be designed such that replaceable or maintainable parts are not interchangeable with parts that would cause the device to exceed its rated flush volume. This requirement, to the extent it can be controlled through this specification, is designed to help prevent the intentional or unintentional change from the product’s rated flush volume to a higher flush volume, which could not only reduce water savings, but impact the product’s performance (e.g., the urinal may flood) as the flushing device and urinal fixture are no longer matched to perform with the same flush volume. For example, a flushing device rated at 0.5 gpf that accepted existing replacement1.0-gpf pistons or diaphragms would not be a product that meets WaterSense’s intentions for this requirement.

All statistics from U.S. EPA WaterSense website.

Anish Desai
Senior Vice President of Product Certification at IAPMO R&T

Last modified: December 29, 2022