107
CHAPTER SEVEN
WATER
7.1 Theory
L
EED Lab approaches water use in the Water Efciency
(WE) set of credits holistically, combining all uses of water
on a building site: indoor, outdoor, specialized uses (e.g.,
HVAC, showers in a dormitory or hospital, water fountains), and
metering. The reason is to calculate present water efciency, to
propose methods to reduce usage of potable water, and then to
address through credits the use of non-potable water and alter-
nate water sources.
Concern over water usage and disposal in a building is very
important due to the increasing scarcity of fresh water and the
environmentally unfriendly manner in which waste water is treated
in most commercial buildings. Developed nations rely upon exten-
sive piping systems to deliver potable water from far away sources,
and then upon another system of conduits to take waste water
to a processing plant, where the waste water – though treated –
still contains contaminants but is nevertheless reintroduced into
the environment by emptying into bodies of water.
1
Further, the
energy expended in treating waste water or in purifying it for drink-
ing, and in the transportation to and from the required locales,
consumes great amounts of energy.
This category of building assessment also introduces alter-
native sewage conveyance techniques as another method to
minimize water consumption. The USGBC has estimated that in
the United States, buildings account for 13.6 percent of potable
water use.
2
Through the avenues presented in this category,
water in building consumption can be reduced or even elimi-
nated by removing the need for irrigation, the installation of
water-efcient xtures and reusing water. LEED projects have
already signicantly reduced water usage in the United States,
and through the use of the WE category’s three major com-
ponents (indoor water, irrigation water, water metering), and
projects can add to this achievement. There are similar goals of
water reduction across other global green rating systems.
DOI: 10.4324/9780429449703-7
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