Water Usage in Buildings

While the efficiency of plumbing fixtures comes immediately to mind when thinking about water conservation, concerns about water usage affect many other categories of building products. Just as many buildings attempt to go off the power grid by generating electricity on site, designers are now looking for ways to take buildings off the water grid by collecting and reusing water on site. Roofing, wall cladding, and sitework must all be re-evaluated in terms of their use in water systems. On-site water storage and processing requires new types of tanks and structural systems. And surfaces that are self-cleaning or otherwise reduce the amount of water used for maintenance are being introduced.

A conceptual study of a highrise designed to optimize rain collection illustrates the growing interest in water efficient architecture. Designed by architectural student:
they decided to design a tower, whose structure will allow for capturing and processing as much rainfall as possible to provide ... water for its inhabitants.  ...we focused at shaping and modeling the surface of the roof to capture as much rainfall as possible. Under a roof's surface, there are water reservoirs in the form of a large funnel and reed fields, which serve as a hydro botanic water treatment unit. The unit processes water into usable water that is further transmitted to apartments. 
A network of gutters on the external surfaces of the building is designed to capture rainfall flowing down the building. such flowing rainfall is transmitted to floors and its surplus is stored in a reservoir under the building. water captured and processed by the building may be used for flushing toilets, feeding washing machines, watering plants, cleaning floors and other domestic applications.
As is appropriate for a student project, the design is more of an exploration of ideas than a practical scheme for construction, but suggests where design may go when water becomes part of the design program. (For the record, one of my student projects, during the 1970's, also focused on water conservation and was equally idealistic. I became so wrapped up in the theoretical implications that I never finished the presentation drawings.) 

For product managers looking into water-usage related opportunities, McGraw Hill has recently published:
Water Use in Buildings: Achieving Business Performance Benefits through Efficiency

This 40-page printed report (available as hard copy or PDF) reviews the role of water efficiency in buildings.  Among other topics, the report covers: involvement and importance of water efficiency, business benefits of water-efficient practices and methods, drivers and obstacles to water efficiency, types of water-efficient products and methods and sources of information behind product selection and use.
Charts throughout the report demonstrate detailed information and successful strategies in order to take advantage of opportunities in the water-efficiency market. For example, the top two motivators to the incorporation of water-efficient practices & products are illustrated in chart form. Energy use reduction is the number one motivator at 78%, and operating cost reduction is 84%. High-efficiency toilets, water-saving sinks, and waterless urinals are all products associated with these cost reductions.
The link between energy and water continues to become transparent and widespread. Both government drivers and the desire to lower energy costs are expected to lead to faster adoption of water-efficiency products and practices. This report finds that 85% of industry players rank water efficiency as a very important part of a green building in 2013, up from 69% in 2008.  Overall, the report research finds that water-efficient products and practices have been embraced for the green buildings of tomorrow.