Without a doubt, waterless urinals are “green” plumbing fixtures because of their water-conservation potential. But their optimum performance lies in how the trap seal is maintained.

For the past seven years, PM Engineer has paid close attention to waterless urinals - from their initial mention in the magazine (July 2001 issue), to their ever-expanding use in commercial plumbing structures, to their recent recommended acceptance by the IAPMO Technical Committee (June 2008 issue, page 6).

More importantly, PME readers have paid attention to waterless urinals as well. A water-conservation survey by PME of more than 1,500 readers in Oct. 2004 featured two questions related to non-water-supplied urinals (as they’re officially called). The first was: “What part of plumbing design was used to obtain LEED points?” Non-water-supplied urinals came in second place, receiving 33% of the vote.

Readers were also asked, “Which water conservation measure, beyond plumbing code requirements, have you implemented in your design?” Nearly one-quarter said non-water-supplied urinals.

Waterless urinals have been around since the early 90s, but their real market growth/acceptance has taken place in the past decade as water conservation has increased in importance and more engineers have become acquainted with data showing the fixtures’ water-conservation potential of thousands of gallons per fixture per year.¹

For example, in Brisbane (Australia), flush urinals are rarely seen because high-level water restrictions have led to mandated conversion to waterless urinals².

Initial criticisms of the waterless urinal included excessive odor and build-up of waste matter. As the following summaries from manufacturers indicate, these two concerns have been overcome through improved urinal design - in particular, the maintenance of the trap seal.

[Editor’s Note: All U.S. manufacturers of waterless urinals were invited to participate in this article, but some chose not to. For more information, be sure to contact each particular manufacturer.]


Kohler: Steward Series

Overview: Kohler Steward waterless urinals come in two models. The Steward S offers a clean, minimalist design making it ideal for new construction. The Steward waterless urinal features a large footprint, making it perfect for retrofitting, as it will easily replace most wall-hung urinals - in most instances without re-tiling or rough-in changes to the waste pipe.

These urinals were developed to provide outstanding performance while passing along to commercial users a potential water savings of up to 40,000 gallons of water per fixture per year, versus a standard 1.0-gallon urinal based on the same usage. The geometry of the urinal not only provides a fresh, architectural design, but also virtually eliminates splashing. Additionally, the touch-free operation improves hygiene for all users and is more vandal-resistant due to the absence of a flush valve.

How Trap Seal Is Maintained: Unlike other waterless urinals in the marketplace, which utilize a cartridge that must be periodically replaced, Kohler waterless urinals feature a cartridge-free integral trapway that is filled with the company’s waterless urinal sealing liquid. The unique design of the trapway allows liquid waste to pass through the sealing liquid and into the waste pipe. Once the liquid waste has passed through, the less-dense sealing liquid maintains its position at the top of the trapway, thus providing an impermeable barrier that blocks odors.

Daily maintenance requires spraying down the surface of the urinal with the company’s waterless urinal cleaner and wiping it clean. Bimonthly, or less frequently (depending on usage), a couple gallons of water are poured into the urinal to purge the system of liquid waste and the old sealing liquid. Then the urinal is replenished with three ounces of new sealing liquid.



Caroma: H2Zero Unit

Overview: Caroma, which provides a range of high efficiency dual-flush toilets and urinals, is introducing the H2Zero waterless urinal in July 2008. The urinal utilizes breakthrough technology to use zero water for optimum performance and water conservation. Made of vitreous china, the urinal addresses key challenges that have been associated with other waterless urinals, including performance, operation, odor management, durability, and waste build-up.

How Trap Seal Is Maintained: The H2Zero’s unique patented cartridge technology does not use an oil-based seal, as traditionally used in waterless urinals. Within the cartridge is a Bio Fresh deodorizing block that is activated during use. The Bio Seal allows urine to pass through the seal freely, eliminating unnecessary waste build-up within the cartridge. The Bio Seal also acts as a one-way airtight valve to seal the cartridge from the drainage system. As urine flows into the cartridge and around the Bio Fresh deodorizing block, heat from the urine activates and emits a lemon fragrance. The urine then flows through the Bio Seal valve and into the drainline. The Bio Seal closes, protecting against back-pressure situations. This operation guarantees superior performance and hygiene.

To service the urinal, the H2Zero’s cartridge tool is used to remove the grate and access the internal components. The Bio Fresh deodorizer and Bio Seal can then be removed and replaced as required. This touch-free tool ensures no direct contact with the replacement components, and no special disposal method is required.



Falcon Waterfree Technologies, LLC

Overview: Falcon offers a series of five waterless units: F-1000, F-2000, F-3000, F-5000 and F-9000SS. All units feature a replaceable cartridge, which is made of 100% ABS plastic (that can be recycled or placed in normal disposal) and contains biodegradable liquid sealant that provides an odor barrier. The company says their urinal is the only one on the market with a patented bayonet lock that provides a tamper-resistant, airtight seal. Its design and performance satisfies all U.S. plumbing and building codes for trap seals, including IPC, UPC, and NSPC. There is no reliance or dependence on any moving part or mechanical device.

Falcon says its urinal’s adaptive drain line coupling is the only one on the market that guarantees downhill slope in the horizontal pipe nipple, ensuring proper pitch for the urinal to drain properly and preventing any waste accumulation.

How Trap Seal Is Maintained: The liquid trap seal used in the Falcon waterfree urinal is calculated by the California Institute of Technology to be 500 times more effective against back-migration of sewer gases as compared to conventional P-trap water barriers. The cartridge is replaced on average 3-4 times per year, and this simple process takes less than five minutes with no hands-on contact with the cartridge or urine.

The liquid sealant does not need to be replenished between cartridge changes due to the patented design of the sealed cartridge. Sealant is provided free of charge and included with new cartridges. A proprietary, non-soy formulation that never evaporates or goes rancid, the sealant contains no hazardous content and is safe for disposal into sewage or septic systems. It is also safe for wildlife in the unlikely event that it should reach lakes, streams, or the water table.



ZeroFlush: ZF Series

Overview: ZeroFlush makes three waterless urinals: ZF-101, ZF-201 and ZF-301. Similar to how the low-flow toilet technology has improved with time, later generations of ZeroFlush waterless urinals have met the challenge of improving existing systems. The ZF units offer easy maintenance and odor-free operation.

How Trap Seal Is Maintained: The company’s patented trap allows urine to flow through an insert that is locked into an internal housing, which is connected to a normal drain. Inside the trap, directly below the insert sits 12 ounces of blue Odor Barrier liquid. This seals the urine in the trap and prevents odors from exiting the system.

The ZeroFlush system allows urine to pass through the housing while it collects most of the uric sediment in the trap itself. The design of the trap allows this sediment to exist in the trap while under normal operation.

After an average of 15,000 uses, this sediment forces the Odor Barrier level in the trap to rise to the top of the insert. This indicates to the janitorial staff that the insert needs to be changed. Changing the insert is easy, clean and fast. Simply pull the insert with an insert-removal tool and let the trap housing drain out. Then rinse the housing with a bucket of water, install the new insert, and add water and Odor Barrier liquid.



Sloan Valve Co.: WES Series

Overview: A heavy-duty, patented cartridge is the main component of Sloan’s WES Series (Models 1000, 2000, 4000 and 5000). A biodegradable liquid sealant is contained within this patented cartridge, which is installed at the base of the urinal and engineered to last for an average of 7,000 uses.

Designed as a replaceable, recyclable component, the cartridge is both installed and removed with a provided key.

How Trap Seal Is Maintained: The biodegrable liquid sealant forms a barrier between the drain and the open air, which eliminates odors. Urine enters the drain holes in the top of the cartridge, passes through the sealant, continues through a trap system and flows over a baffle to prevent the loss of sealant. The cartridge collects uric sediment. A discharge tube in the housing directs the remaining liquid, which is non-corrosive and free of hard water, into the drainage pipe. The result: No wasted water and an odor-free environment.


How Sloan Waterfree Technology Works

The cartridge acts as a funnel directing flow through the liquid sealant (1), preventing any odors from escaping. Next, the cartridge collects sediment (2), allowing the remaining waste to pass freely down the drain (3).


Waterless Co. LLC: No-Flush Series

Overview: Waterless Co. LLC says its No-Flush urinals have been installed in high-traffic facilities for the past 18 years. The company currently offers six models, which install easily: Yukon, Sierra, Kalahari, Sonora, Del Mar and Del Casa. The urinals work best and achieve their highest savings in high-traffic facilities. Each urinal comes with two EcoTraps. Other advantages include low cost of the trap, no trap insert to be taken apart for service and the system offers a full 2" interior drain line.

The company says it is the only one to offer both ceramic and High Performance Composite urinals. In addition, the company offers boom drain urinals for easy trough conversion, as well as the only urinal made partially from soybean resin, a renewable resource.

How Trap Seal Is Maintained: The EcoTrap insert sits in the urinal bowl by a simple press fit and is filled initially with water and BlueSeal sealing liquid. Three ounces of BlueSeal will last for approximately 1,500 uses and then is simply refilled, without the need to remove or touch the trap.

The EcoTrap will last for 7,000 to 10,000 uses until it fills up and needs replacement. To replace, use the X-Traptor tool to wiggle the EcoTrap loose out of the drain hole in the urinal (to avoid spillage), then empty the liquid contents into a plastic bag. Unhook the trap, then place it inside the plastic bag. Discard in a locally appropriate manner.

Pour water into the drain hole to flush the drain line, then fill a new EcoTrap with water under the sink and set into the urinal drain hole. Be sure to press it below the drain hole rim, then add 3 oz. of BlueSeal.




¹ Wikipedia [http://en.wikipedia.org]; Urinal article, “waterless urinals” section.

² Comparison data versus a standard 1-gallon urinal based on the same usage.