Thirteen companies have now committed to the California Best Buildings Challenge to significantly reduce their energy, water, and waste footprints, up from the original six companies that signed on at the challenge's launch in June. The participating companies represent more than six million square feet of collective building space.

Participants have specifically committed to pursuing reductions of energy consumption, potable water consumption, and the generation of landfill waste in one or more buildings by 20 percent in two years. Participants also have agreed to share their consumption data with the USGBC’s Northern California chapter (UGSBC-NCC). Additional companies may enter the challenge by signing a commitment letter no later than Oct. 25.

To participate, the companies will establish data for both a baseline year and a performance year. The baseline year represents any 12-month period between 2011 and 2012. The improvement year is the 12-month period following the baseline year. During this time, projects will make performance improvements, and this time frame will be followed by the performance year, a 12-month period where data is collected and then compared to the baseline year statistics.

The challenge was launched at the closing plenary event of the 2012 Clinton Global Initiative America (CGI America) in June, and was developed by USGBC-NCC. Below is video of the original launch:

Committed companies include Adobe, Genetech, Google, Prudential Real Estate Investors, SAP, and Zynga. More information on the participants and the challenge can be found here.