Solar on Multifamily Affordable Housing in California


In December 2017, California adopted the Solar on Multifamily Affordable Housing Program (SOMAH) to provide low-income tenants with access to clean energy. The maps and charts below provide information on multifamily affordable homes and solar potential related to the SOMAH program.

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  7. For details on the data and methodology, please refer to the Notes below.
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1 The SOMAH program implements Assembly Bill 693 through Decision D.17-12-022 of the California Public Utilities Commission (CPUC).

2 To be eligible for the SOMAH program, a multifamily building must be located in a disadvantaged community (see Note 3) OR at least 80% of the households in the property must be classified as low-income(see Note 4).

3 Disadvantaged communities (DACs) are areas that score in the top 25% of census tracts statewide on the California CalEnviroScreen 3.0 metric. Census tracts that do not have an overall CalEnviroScreen score but are in the highest 5% of CalEnviroScreen’s Pollution Burden indicator are also designated as disadvantaged communities.

4Low-income households are households with incomes at or below 60% of the area median income (AMI) as defined in subdivision (f) of Section 50052.5 of the Health and Safety Code.

5 The database of multifamily affordable households used for this map was compiled by the California Housing Partnership Corporation (CHPC). For more details visit:

6 The rooftop solar potential estimates for each building were sourced from Google Project Sunroof. Some of the estimates may not be accurate especially for properties with multiple buildings. Not every building in our database is in the Google Sunroof coverage area. The “Max kW DC” is the maximum system size that could be placed on the roof, including north-facing roof planes and other places that are not economically sound choices. The maximum panel layout is limited to 1 MW (or 4000 panels with a 250W nominal size for each panel).

7 There are six investor-owned utilities (IOUs) in California: Pacific Gas & Electric (PG&E), Southern California Edison (SCE), San Diego Gas & Electric (SDG&E), PacifiCorp, Liberty Utilities and Bear Valley Electric Service (BVES). Many of the multifamily affordable buildings in California are located in publicly-owned utility (POU) territories labeled “n/a” on the map and colored in grey. These properties are not eligible for the SOMAH program.

Contact Us

For questions, comments, or to report any errors in the data, please email Dr. Boris Lukanov at These data are accurate to the best of our knowledge, but there may be discrepancies in data aggregated from multiple sources and or errors introduced during the compilation. We appreciate your feedback.