Leadership in Energy and Environmental Design (LEED) is a system that rates and certifies buildings for how eco-friendly, or environmentally friendly, the building is. It looks at things like how much energy and water the building uses, the type of materials used to build the building, and how the building is making efforts to reduce its impact on the environment. When a building earns a LEED certification, it means that it is designed and built in a way that helps keep the environment healthy and protect it from harm!