The California Building Standards Commission has approved Calgreen as the first mandatory state-wide green construction code to be adopted in the US.

California’s Governor Arnold Schwarzenegger said the code will help to meet the goals of curbing global warming and achieving 33% renewable energy use by 2020, according to

“The code promotes the development of more sustainable communities by reducing greenhouse gas emissions and improving energy efficiency in every new home, office building or public structure,” Schwarzenegger said.

The code, developed from voluntary green building standards enacted across the state in 2008, is expected to come into effect from January 2011.

The code lays down the baseline for all new buildings with optional tiers that local jurisdictions can incorporate for higher levels of performance.