3-4
WaterSense at Work: Best Management Practices for Commercial and Institutional Facilities
Overview
Toilets, or water closets, can be found in nearly every commercial and institutional fa-
cility. Several types of toilet technologies are installed in commercial and institutional
settings, including tank-type toilets, flushometer-valve toilets, and less commonly,
composting toilets. Toilets currently on the market can perform well (i.e., adequately
clear waste) while using less water than older models installed before the Energy
Policy Act (EPAct) of 1992 maximum flush volume requirements were established.
Tank-type toilets are designed with tanks that store and dispense water to the toilet
bowl to flush waste. Varieties of tank-type toilets include the standard gravity type
(
found in most homes), pressure-assist (or flushometer-tank toilets), and electro-
mechanical hydraulic toilets. Tank-type toilets are available as single, constant-
volume flushing models or as dual-flush models, which include a full flush for solids
and a reduced flush for liquids. Tank-type toilets are commonly found in residential
and light commercial settings.
Flushometer-valve toilets are tankless fixtures with ei-
ther wall- or floor-mounted bowls attached to a lever- or
sensor-activated flushometer valve that releases a specific
volume of water at a high flow rate directly from the water
supply line to the bowl to remove (i.e., flush) waste. Unlike
tank-type toilets, which store water in the tank to provide
the necessary pressure and flow to remove waste from
the bowl, flushometer-valve toilets rely on larger diameter
water supply piping and high water supply line pressures
to remove waste. These fixtures are also available as single,
constant-volume flushing models, or as dual-flush models.
Flushometer-valve toilets are used predominantly in public-
use facilities and high-use commercial settings. Flushome-
ter-valve toilets include blowout and rear discharge toilets,
which have bowls that remove waste slightly differently
than standard siphonic bowls.
Flushometer-valve toilets can be equipped with electronic
sensors, which trigger the flushing mechanism when a
user has finished using the fixture. Sensors themselves
provide no additional water-efficiency benefits; however,
they provide health and sanitation benefits in public-use
facilities since they offer a hands-free option. If not properly
programmed, operated, and maintained, automatic flush sensors can cause double
or phantom flushing, which increases the water used at a facility.
EPAct 1992 established the maximum allowable flush volume for gravity tank-type,
flushometer tank (or pressure-assist), electromechanical hydraulic, and flushometer-
valve toilets sold in the United States at 1.6 gallons per flush (gpf ). The maximum
flush volume for blowout toilets, which are used primarily in locations subject to high
traffic or heavy use such as prisons, was set at 3.5 gpf. Due to the long, useful life of
3.2
Toilets
Flushometer-valve toilet
