1119-1121 Mason St, San Francisco, CA 94108

The two-unit residential building at 1119-1121 Mason Street in Nob Hill, owned by Walter Chan and Yan Li, is a two-story flats and duplex structure dating back to 1940. The property has undergone several significant maintenance and repair work over the past decades, including a complete stairway replacement on the right side of the house in 2014 (cost: $10,000), re-roofing work in 1995 (permit expired), and concrete footing repairs in the garage area completed in 1991.

The building has experienced recurring sewer-related issues, with documented sewage backups through a 4-inch vent occurring in 2018, 2019, and again in 2020-2021, suggesting an ongoing plumbing infrastructure concern despite these incidents being marked as resolved through proper work orders. Additional incidents affecting the property environment included a water main break in December 2010, maintenance on damaged trees in October 2018 (hanging limb) and August 2019 (fallen tree), and one instance of offensive graffiti on a sign in March 2018 that was addressed by the sign shop.

An abandoned vehicle was reported near the property in May 2011, though it was resolved when officers arrived at the scene. While the building's major structural elements have received periodic attention, the recurring nature of sewer issues stands out as a notable pattern in the building's maintenance history.