Tankless toilets, which include urinals, are by far the most common type of toilet found in public restrooms. The vast majority of these units operate using a valve, which is metered with either a piston or diaphragm. The valve is designed to shut automatically after completing a flush cycle, so there is no computer or other technology that regulates the operation.
In the world of plumbing, traditional flush valve tankless toilets are considered low-tech yet reliable workhorses. However, there can be some degree of user control with these devices. For most models, building owners can make minor adjustments to flush volumes, though in the United States and many other countries they must comply with national standards for water usage. A number of features can also enhance the performance of a flush valve toilet in commercial settings, including hands-free flush technologies and water conservation devices.
Within commercial settings, all tankless toilet models pretty much work in a similar way. When a toilet is flushed, a valve opens a supply line to allow a predetermined amount of water to pass through into the bowl. According to the U.S. Department of Energy, the current standard for water usage in the U.S. is 1 gallon (3.8 liters) for urinals and 1.6 gallons (6 liters) for regular toilets [source: Department of Energy]. The standards are similar or even stricter in other parts of the developed world, such as Australia, where average flush volumes must not exceed 0.6 gallons (2.2 liters) for urinals and 1.5 gallons (5.5 liters) for toilets [source: Australian Government].
Recently, one of the biggest trends for tankless toilets in commercial settings has been hands-free flush technology [source: Koeller]. This feature can be powered by battery or hard wiring, but there is typically a manual flush mechanism that still operates in the case of power failure. Hands-free flushing is beneficial in that it helps prevent the spread of germs. However, there is a common problem with this technology: Automatic flushers can misfire, leading to either wasted water or leftover waste.
For the most part, water pressure in commercial plumbing systems is high enough to power the flush of tankless toilets. Because water pressure in residential buildings and private homes is not as strong, it has limited the use of tankless toilets in many U.S. homes over the past century. There are some exceptions to this rule, which we will discuss in the next section.