Green building is burgeoning across the United States. Most builders concentrate on residences or commercial structures such as large office buildings, healthcare facilities, and retail centers. Few give thought to the small buildings that, although often perceived as inconsequential, also play a significant part in our lives.

Capitalizing on the potential of these facilities, the New York–based Wildlife Conservation Society’s Eco-Restroom (above) in Bronx, N.Y., provides a potty break to more than 2 million visitors per year without negatively impacting the nearby Bronx River. Located at the Northeast entrance to the Bronx Zoo, the 2,400-square-foot Eco-Restroom, designed by Edelman Sultan Knox Wood Architects in New York, features a Clivus Multrum composting toilet system that conserves water and prevents waste from becoming a source of pollution.

Using a mixture of biocompatible soap and water, foam-flush toilets need only a few ounces of water per flush. In fact, each toilet uses 99 percent less water than a conventional toilet. Waste then is stored in large bins in the restroom’s basement where wood chips and small organisms (including bacteria and fungi, as well as invertebrates such as red worms) process it into rich soil rather than feed it into the city’s wastewater system.

Eighty-five percent of the structure’s footprint covers a site previously occupied by a pre-existing, abandoned restroom. Swales around the building direct stormwater to a rainwater garden, and roof leaders connect to both rain barrels and the rainwater garden. A graywater garden in front of the building provides biofiltration for wastewater from the hand-washing sinks.

Inspired by both the trees surrounding the site as well as by the Bronx River, the cedar-clad, wood-framed structure features wooden load-bearing walls with translucent glass infill at the non-load bearing ends. The restrooms (left) have sloped ceilings with exposed wooden rafters, and skylights span the width of each room, bringing in an abundance of natural light. Slate floors and other materials with high recycled content were sourced locally. The result? A pit stop that's a relief to both its users and Mother Nature.