Waterless urinals are truly waterless. They don't use some water, or a little water. They use no water. So the amount of water you can conserve by installing one is essentially equal to the amount of water used by the urinal it replaces. Most urinals in use today use somewhere between 1 and 3 gallons (3.7 to 11.3 liters) of water for each flush [source: Reichardt]. That variance is so large because older urinals use a lot more water, and newer ones tend to use less (because of an increased focus on conservation). Urinals produced during the 1990s and '00s use closer to 1 or 1.25 gallons per flush [source: Stumpf]. Some extremely low-flow fixtures use even less. Older urinals can use closer to 3 or 3.5 gallons (11.3 to 13.2 liters) of water for each flush [source: Stumpf]. Other variables include the amount of use the urinal gets. A urinal in a busy office where 100-plus men work will use more water than one located in a small restaurant or gas station. Taking all of the variables into account, a single urinal in a workplace with a few dozen employees can save about 45,000 gallons (about 170,000 liters) of water per year [source: Stumpf].