Codes and standards for design and construction are nothing new, and for many decades builders have "worked to code" depending on the location of the project. States and even regions within states have the power to choose which codes will govern projects, so there is a lot of variety from coast to coast. In green building, this has led to a lot of creativity in getting green innovations up to code when the methods and materials aren't even included in traditional standards and code books.
LEED, Leadership in Energy and Environmental Design, developed by the U.S. Green Building Council (USGBC), is a system for certifying projects that meet high standards in green building and design. Projects focus on "energy savings, water efficiency, CO2 emissions reduction, improved indoor environmental quality, and stewardship of resources and sensitivity to their impacts" [source: USGBC]. Both residential and commercial buildings, as well as entire communities, are eligible for LEED certification, and even building professionals can become LEED certified in their areas of specialization. A stringent review process takes place, and there are fees for applying for certification, but a LEED certificate carries international prestige and recognition in the green arena. A home doesn't have to be LEED certified to be green, but many LEED practices and its high standards set the bar for how far a home can go in the right direction.
California leads the way at the state level with its 2010 California Green Building Standards (CALGreen) Code. With guidelines for applying green building practices, the code applies to all residential and commercial projects from January 2011 onward. As it takes the lead, other states across the nation and other regions of the world can learn by keeping up with building reports from California. With customized codes for the climate and high rate of seismic events, not all specifications will fit all locales, but as a basis for developing similar initiatives, CALGreen is the first of its kind.