Consider the building you are in right now. Water is actively flowing through its plumbing, used for drinking, cleaning, flushing toilets, taking showers, and so on.
But there is also water that you don’t see, water used to manufacture all the different building materials and to produce the energy used in manufacturing as well. This is the so-called ‘embodied water’ of the building.
Some water is directly used during construction—water is an essential ingredient of concrete, for example, chemically reacting with cement to form the binder that holds the material together. But much more water is used ‘upstream’ from the actual construction process, for processing minerals into metals or providing steam and cooling water to power plants.
For a typical building, steel contains the highest embodied water, followed by concrete and then, perhaps surprisingly, carpets. Each square foot of floor space requires more than 1,000 liters of embodied water.
For this building, part of the Boston Conservatory of Music, the total embodied water for construction exceeds 150 million liters, enough to fill a glass 200 feet wide and 180 feet high, towering over the building itself.
 McCormack, M., G.J. Treloar, L. Palmowski, and R. Crawford. 2007. Modelling direct and indirect water requirements of construction. Building Research and Information, 35(2): 156-162.