The controversy began in early 2005 when the Council ruled that waterless urinals would not be included in the United States’ Uniform Plumbing Code.

That decision was subsequently appealed by waterless urinal manufacturer, Falcon Waterfree Technologies, which secured the support of 20 California water districts in presenting its case.

However, at the November appeal hearing, the anti-waterless-urinal case was argued by a sanitary engineering expert, supported by the California State Pipe Trades Council in association with grass-roots lobby group, Communities for a Better Environment.

Dr Fox argued that “… the no-flush urinal ignores hard-learned lessons on sanitation and reverses over a century of practice by failing to provide consistent cleaning of the urinal wall and replacing the permanent seal with one that has to be changed every 30 to 90 days.”

Furthermore Dr Fox noted apparent deficiencies in waterless urinals relating to alleged sewer gas leakage, odor, wall deposits, sealant integrity, pipe deposits, maintenance and aerosolization.

It was a compelling argument. After all, the main function of the permanent water seal and flush action in modern toilets and urinals is to prevent sewer gases and pathogens – such as dysentery, typhoid and SARS – from finding their way into the bathroom or restroom environment.

Yet waterless urinals have been installed in many different kinds of buildings in the US including schools, universities, sports stadiums, McDonalds' restaurants, Wal-Marts, resorts and offices.

For every reported failure, you’ll find a success story about how the flush-free fixtures have brought water savings and other benefits to that facility without apparent health problems.

So what’s the case for waterless urinals – and should they be allowed in the US and other countries with rigorous national plumbing Codes?

Floating barrier to sewer gases

The United States National Energy Policy of 1992 requires urinals manufactured after 1 January 1994 to use no more than 3.78L (1 gallon) per flush. The previous standard was 11.35L (3 gallons) per flush, but higher flush volumes are common in older buildings.

This means that replacing urinals in a facility more than 10 years old with water-free ones offers an opportunity to save water, sewer, installation and maintenance costs, since they require no water to flush, no piping, and no flush valves or other control hardware.

According to European company Ernst (www.ernstsystems.com), the first water-free urinal was invented in 1894 by Swiss engineer Fritz Ernst.

The modern Ernst Water-free Urinal is a specially designed syphonic trap containing a biodegradable, low-density, viscous barrier liquid that floats on top of the urine to form a seal. This floating seal prevents drainpipe odors from coming back into the restroom.

Most water-free urinals available today – such as Falcon, Uridan, Duravit, Waterless and McDry – also use this floating seal principle, based on a barrier liquid either supplied in a pre-measured amount with a replaceable cartridge, or as a refill for topping up liquid seal traps at specified intervals.

There is another type of no-flush urinal with a mechanical trap that automatically closes after use. Brands based on this principle include Franke, Keramag and Sphinx. (US sources interviewed for this story stated that the US Code prohibits the use of traps with moving parts for protection against sewer gases.)