The area’s greenest buildings? We asked the US Green Building Council, whose Leadership in Energy and Environmental Design (LEED) certifications rank buildings at four levels. There are 11 LEED-certified buildings in the Virginia suburbs, 15 in Maryland, and 21 in DC. Three buildings in the region have the highest status.

The District’s Sidwell Friends middle school, built with recycled materials such as red cedar from wine casks, uses only 40 percent of the energy that similarly sized buildings do and incorporates a constructed wetland to recycle wastewater, earning it the highest status in 2007.

Joining the elite group is the Philip Merrill Environmental Center (named after the late owner of The Washingtonian), home to the Chesapeake Bay Foundation in Annapolis. The building was designed to have minimal impact on the bay, using geothermal wells positioned 300 feet underground to help heat and cool the space, southern exposure to maximize natural light, and waterless composting toilets to reduce wastewater.

Virginia buildings haven’t earned top status, but One and Two Potomac Yard in Crystal City, home to the Environmental Protection Agency, are among the region’s greenest. Most construction materials were bought regionally from eco-friendly companies, 100 percent of its power comes from renewable energy, and the space uses green heating, roofing, and lighting.