118-120 21st Ave, San Francisco, CA 94121

The two-unit residential building at 118-120 21st Avenue in the Lake-Presidio neighborhood is a two-story flats and duplex structure built in 1911 and currently owned by Daniel Y Wong. The property has experienced several significant maintenance and safety issues over the past decade, most notably a recent active complaint filed in November 2024 regarding a carbon monoxide leak from a basement water heater setup that also raised concerns about cramped plumbing and electrical conditions. A 2023 complaint about blight mentions concerns regarding a deteriorating rear structure affecting an adjacent fence.

The building underwent some voluntary compliance work in 2010 following physical inspection report #CC-5642, which included electrical upgrades and plumbing corrections, though these permits have since expired. Earlier building modification attempts in 2005 for vertical and horizontal additions were withdrawn. The property has undergone several regulatory processes, including condo conversion applications that were ultimately approved.

Historical complaints from 2014 noted concerns about tree root damage to a brick wall. While the building's major systems have received some attention through permits and inspections, the most pressing recent concerns appear to be related to safety systems and building maintenance. The property has generated numerous 311 calls between 2019-2022, though these primarily relate to parking violations and street cleaning issues rather than building-specific problems.