San Francisco needs housing. San Franciscans love the character of our buildings and neighborhoods. Gentle density allows the city to provide more housing, suited to our diverse households. It does so in ways that enhance the qualities we love about neighborhoods. It empowers local people to create better buildings and neighborhoods for themselves, their households, and their community.
What is gentle density?
Gentle density, Missing middle housing, incremental development are related terms which describe a range of housing types as well as a philosophy and set of practices for how cities grow and change.
Missing middle housing is the rich set of housing types which are denser than single-family houses but smaller than large apartment buildings. It includes in-law apartments, townhouses, stacked walk-up flats, cottages and cottage courts, and small apartment buildings, and the storefront commercial and live-work spaces which make neighborhoods convenient and walkable.
Incremental development draws on the missing middle types, but add the dimensions of of care, character, and adaptability. The Incremental Development Alliance envisions “neighborhoods regenerated by small developers who care deeply about the places where they live”. Incremental development is about what gets built, but also who builds it – empowering people who live in communities to build the housing their community needs. People building in the communities where they and their loved ones live will build with more care and accountability.
Gentle density won’t address all our housing needs. Gentle density complements large-scale developments – larger buildings on larger sites. We also need to build more permanently affordable and social housing, both large- and small-scale. For decades San Francisco’s housing strategy has favored large developments and paid less attention to gentle density, due in large part of political resistance to incremental development in neighborhoods.
Over the past decade San Francisco has amended its zoning laws, and the state has passed laws superseding local zoning, to permit gentle density. Livable City has helped author and advocate for dozens of ordinances to legalize gentle density. We have legalized new units (called accessory dwelling units) in existing buildings, created a path to legalization for tens of thousands of existing unpermitted units, allowed multi-unit buildings throughout the City, removed off-street parking requirements that make incremental development expensive or infeasible, and permitted neighborhood-serving storefront businesses. The new laws protect existing tenants, and require buildings to meet the street well and enhance streets and sidewalks as public spaces.
The Gentle Density Campaign
3,423 accessory units have been permitted or legalized in San Francisco since 2015. We think the potential is much greater. Thanks to state law changes, accessory dwelling units account for a growing percentage of new California housing. Portland permitted 2,200 missing middle units between 2021 and 2024, roughly six times more than San Francisco. Our Gentle density campaign aims to permit 1000 new missing-middle units by 2030. To make this happen we will advocate for code changes and programs in four areas:
- Additional planning code reforms to facilitate missing middle housing.
- Expand design, technical, and financial assistance to homeowner-builders.
- Building code reforms which ease construction of missing middle housing, including single stair reform.
- Build the bench for incremental development. Expand skills training, peer support, and access to finance for neighborhood developers, small contractors, and the construction and design workforce.
A legacy of reform
- In 2014 Livable City worked with Supervisor David Chiu to provide a path to legalization for thousands of unpermitted units, most of which are rent-stabilized.
- In 2015 we worked with Supervisors Wiener and Christensen to legalize accessory dwelling units in Districts 8 and 3, and then citywide.
- In 2018 Livable City worked with supervisor Jane Kim to remove minimum parking requirements from San Francisco’s planning code, a milestone of Livable City’s successful multi-year parking reform campaign.
- The Fourplex ordinance was approved at the end of 2019, allowing buildings of up to four-units, and up to six units on corner lots, on every lot in the City’s RH districts. This ordinance effectively ended exclusive single-family zoning in San Francisco.
- In 2020 Livable City and the AIA’s PPAC developed 25 recommendations to improve the permitting of incremental housing in San Francisco. Several had been enacted. Livable City drafted the remaining recommendations as planning code changes, which Mayor Breed incorporated into her 2023 constraints reduction ordinance.
