The Department of Resources Recycling and Recovery (CalRecycle) defines a green or sustainable building as ."..a structure that is designed, built, renovated, operated, or reused in an ecological and resource-efficient manner. Green buildings are designed to meet certain objectives such as protecting occupant health; improving employee productivity; using energy, water, and other resources more efficiently; and reducing the overall impact to the environment."
For more information about green building visit the CalRecycle and EPA websites.