(Image credit: Clark Art Institute)

The Clark Art Institute in Williamstown, Mass. has a one-acre reflecting pool, but it's not a waste of water. Rainwater is collected from the rooftops where a simple gravity pipe connects them to the reservoir system, which feeds the water feature, as well as plumbing fixtures, site irrigation, and the site's cooling tower. Emergency overflow from the water feature goes into a nearby brook.

The New Clark Art Institute Reinvents The Museum Fountain For A Sustainable Age | Co.Exist