San Marino is one of the San Gabriel Valley's most exclusive residential communities, known for its tree-lined streets, large lots, and high-value custom homes. The city maintains strict design review standards that influence every aspect of construction, including finish specifications. Renovation and remodel projects are common as homeowners update and expand the area's traditional architecturewhich often requires texture matching to blend new drywall with existing surfaces.

San Marino operates its own building department and is known for a deliberate plan check process. The city's design review board exercises significant influence over architectural character, and finish quality expectations are high. New construction typically calls for Level 4 or Level 5 finishes depending on the architectural style and interior design program. ADU construction is present but moderated by the city's lot sizes and design review process.