Marin County's original Single Family Dwelling Energy Efficiency Ordinance went into effect on January 1, 2003. The building code has grown in strength and scope through the years and the requirements described below apply to the following building projects constructed after June 18, 2010:
* New residential construction over 500 square feet
* All residential remodels and additions
* All new multifamily residential construction
* New commercial projects and additions over 2,000 square feet
* All commercial remodels
'''New Single-Family or Two-Family Homes:'''
New homes built in Marin County have to comply with the building code in two ways. First, the home must achieve a certain amount of points from the GreenPoint Rated rating system for new homes with larger homes being required to achieve more points. Homes between 500 square feet and 2,499 square feet must earn 75 points, and homes 7,000+ square feet must earn 200 points. Between these two levels, there are three other housing size classifications with their own point requirements. Second, all new homes in Marin County must be designed to be a certain amount more energy efficient than the [http://www.dsireusa.org/incentives/incentive.cfm?Incentive_Code=CA51R&re... state building code]. Homes between 500 and 2,499 square feet must be 15% more efficient than the state code, and homes 7,000+ square feet must be net zero energy. Again, there are three other housing size classifications with their own requirements.
'''Single-Family or Two-Family Home Remodels:'''
Homes in Marin County that are renovated or added to are also subject to some requirements of the building code. If the work done to the house totals less than $50,000, the owner must insulate exposed hot water pipes. If the home improvement project includes reroofing, the homeowner must also install a radiant barrier. If a home is undergoing more expensive renovations, the most must meet some level of the GreenPoint Rated rating system for existing homes.
'''Multifamily Residential New Construction'''
New multifamily projects in Marin County where the average unit is less than 1,000 square feet must earn 60 points on the GreenPoint Rated rating system for multifamily homes and be 15% more efficient than the state building code. Multifamily projects where the average unit is 1,000 or more square feet must earn 75 points and be 15% more efficient than the state code.
'''Commercial New Construction'''
Marin County uses the U.S. Green Building Council's Leadership in Energy and Environmental Design (LEED) as the building standard for commercial construction. New construction, including additions to existing buildings, between 2,000 and 4,999 square feet must comply with the prerequisite requirements of LEED New Construction or LEED Core and Shell. Building projects between 5,000 and 49,999 square feet must be certified at the Silver level of LEED New Construction or LEED Core and Shell and be 15% more efficient than the state building code. Building projects greater than 50,000 square feet must be certified at the Gold level of LEED New Construction or LEED Core and Shell and be 15% more efficient than the state building code.
Commercial remodeling projects which cost less than $500,000 or involve less than 5,000 square feet have voluntary energy suggestions, which are not required. Larger projects have requirements which are based on LEED Commercial Interiors or LEED Operations and Maintenance.
In addition to the requirements stated above, new commercial buildings over 5,000 square feet and all new residential construction must include plumbing and electrical conduit specifically designed to accommodate the easy installation of solar water heaters and photovoltaic systems in the future. These systems can be used to comply with the building code, but are not required by the building code. The exact requirements for these solar-ready additions will be adopted by the Chief Building Inspector.