The General Services Administration (GSA) submitted a report to Congress on September 15, 2006 in response to a request from the Committee on Appropriations to "report to the relevant congressional committees…on the progress and next steps toward recognition of other sustainable building rating systems." In the cover letter accompanying the report, GSA Administrator Lurita Doan wrote, "Based on the results of the study, GSA finds that the U.S. Green Building Council's LEED Rating System continues to be the most appropriate and credible sustainable building rating system available for evaluation of GSA projects.”

The evaluation was conducted for GSA by the U.S. Energy Department’s Pacific Northwest National Laboratory. The Sustainable Building Rating System Summary examined five different rating systems: Building Research Establishment’s Environmental Assessment Method (BREEAM); Comprehensive Assessment System for Building Environmental Efficiency (CASBEE); GBTool; Green Globes US; and LEED. In her cover letter, Administrator Doan cited the following reasons for GSA's conclusion:

• LEED is applicable to all GSA project types
• LEED tracks the quantifiable aspects of sustainable design and performance
• LEED is verified by trained professionals
• LEED has a well-defined process for making updates
• LEED is the most widely used system in the U.S.

Administrator Doan also noted that GSA will continue to evaluate the applicability of other rating systems as they develop

GSA is the federal government's landlord and the largest real estate organization in the country,  with more than 340 million square feet of buildings and an additional 90 million square feet currently under construction. GSA was the first federal member of the Council, and currently requires all new buildings and substantial renovations to earn LEED certification, with a target of LEED Silver.