Abandoned 'Lake SoMa' Site in San Francisco to Become 25-Story Tower

New developer plans to build 272-unit high-rise after acquiring property with water-filled foundation

Mar. 17, 2026 at 12:51am by Ben Kaplan

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A long-stalled residential complex in San Francisco's South of Market neighborhood, known as 'Lake SoMa' due to its abandoned water-filled foundation, is set to be redeveloped into a 25-story tower with 272 units. The new developer, Thompson Builders, acquired the site and an adjacent property, and plans to demolish the existing structures to construct the taller, denser project.

Why it matters

This project is one of many in San Francisco attempting to increase density and height in order to become financially viable, as developers struggle with rising construction costs and the city's affordable housing requirements. The redevelopment of the blighted 'Lake SoMa' site is seen as an opportunity to address blight and continue activating the SoMa corridor with new housing.

The details

The new plan for 360 Fifth St. calls for a 257-foot, 25-story tower with 272 units, up from a previously approved 8-story, 127-unit building. The project will also include two 3-story 'wings' along Shipley and Clara streets. Thompson Builders is using the state density bonus to achieve a 100% density increase, with 30% of the units affordable to low- and moderate-income households.

  • The previous 8-story, 127-unit plan was approved in 2018 but abandoned during the pandemic.
  • Thompson Builders acquired the site and an adjacent property at 214 Clara St. in 2025.

The players

Thompson Builders

The new developer that acquired the 360 Fifth St. site and an adjacent property, and is planning the 25-story, 272-unit tower project.

David Chiu

The San Francisco City Attorney who sued the previous owner of the 360 Fifth St. site, charging that the property had become a blighted water-filled hole.

Dan Sider

The Planning Department Chief of Staff, who stated the project has 'a great deal of potential' to address the blighted site and continue activating the SoMa corridor.

Corey Smith

The Housing Action Coalition Executive Director, who said developers are reworking their pro formas to make projects work, including by increasing height and density.

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What they’re saying

“The project has a great deal of potential not just to address this blighted site, but to continue activating the corridor while creating hundreds of new homes.”

— Dan Sider, Planning Department Chief of Staff

“It's cool that (Thompson) is able to make it work. It's a whole different building type than the previous proposal.”

— Corey Smith, Housing Action Coalition Executive Director

What’s next

The project will require conditional use approval from the San Francisco Planning Commission due to the demolition of the single-family home at 214 Clara St.

The takeaway

This project highlights the challenges developers face in making housing projects financially viable in San Francisco, leading them to pursue taller, denser projects that can take advantage of state density bonuses. The redevelopment of the 'Lake SoMa' site also demonstrates the city's efforts to address blight and activate underutilized areas with new housing.