The County Office of Sustainability (COS) was created within the Internal Services Department by the Board of Supervisors in October 2009 to respond to legislation, regulation and policy related to Climate Change and serve as a central hub to coordinate Energy Efficiency, Conservation and Sustainability Programs within the County, its facilities and the region.  It is headed by General Manager Howard Choy and has a staff with expertise in energy efficiency, renewable energy, transportation, climate change, land use planning, green building, conservation programs, grant and contract administration, and marketing and outreach.

The COS develops and implements programs that impact and benefit the constituents of Los Angeles County, such as the Energy Upgrade California in Los Angeles County energy efficiency home improvement and rebate program, countywide Environmental Service Centers, the SolarMap LACounty.gov and Green.LACounty.gov websites, and the Los Angeles Regional Collaborative for Climate Action and Sustainability. In addition, COS is the lead in coordinating and implementing Energy and Environmental policy programs and activities by all County departments.