The San Francisco Municipal Transportation Agency is replacing the century-old Potrero bus yard at 2500 Mariposa Street with a four-story bus maintenance and storage facility. Construction has begun and runs through 2030. The work zone covers a superblock bounded by Mariposa, Bryant, 17th and Hampshire streets.
The yard supports more than 800 staff. The rebuild changes daily travel for the operators and maintenance crews who work there.
Work windows a shift planner can use
Construction hours run primarily 7:00 a.m. to 8:00 p.m., Monday through Friday. Overnight work is anticipated to be intermittent. Noise is expected during construction.
Three contacts carry the operational questions. Webcor leads construction. General construction questions go to PotreroYard@plenaryamericas.com. Noise complaints go to 415-234-8190 or PotreroYardSF@webcor.com. Bidding and job questions go to outreach@webcor.com.
Six routes, one yard
The routes stored and maintained at Potrero Yard are the 5 Fulton, 5R Fulton Rapid, 14 Mission, 22 Fillmore, 30 Stockton and 49 Van Ness/Mission. The agency states that all six serve Muni Service Equity neighbourhoods.
Trolley buses powered at the yard provide emissions-free service to about 97,500 bus riders each weekday, the project page states. Staff who ride the 14 Mission, the 22 Fillmore, the 30 Stockton or the 49 Van Ness/Mission ride routes the yard supports.
The project page states that the rebuilt yard becomes the central hub for the agency's zero-emission trolley bus fleet. It records room for an additional 100 trolley buses, a 68 percent increase over the current design capacity. State regulations set 2040 for zero-emission transit fleets.
Lane shifts and temporary parking loss
Travellers should expect temporary lane shifts around the site. Signage and cones mark and section off work zones, and the agency advises attention to changing traffic patterns.
Temporary parking restrictions apply inside active work zones.
Phase timing on the record
The project page lists design and permitting across 2022 to 2026, construction across 2026 to 2030, and the start of operations in 2030. Site preparation begins later this year, ahead of demolition expected to start in early 2027.
City permit records carry two entries for the site. A demolition permit, number 202608196855, was filed on 8 September 2026 for a two-story type 1 auto repair building with an estimated cost of $4.5 million, and it sat in filed status. A new-construction permit, number 202411084679, was filed on 8 November 2024 for a four-story type 1a bus maintenance facility with an estimated cost of $400 million, and its last recorded activity was 23 September 2026.
No finer phase calendar is published for staff.
The 21 October construction update
Webcor gives a virtual community construction update on Wednesday 21 October at 5:30 p.m. The contractor will cover construction details and what to expect in the current and upcoming phases of work.
What the rebuilt yard delivers
The project page records four gains for staff: faster bus repairs, green infrastructure, room for fleet growth, and improved work conditions for more than 800 staff.
Housing on the same block
The page records up to 100 units of proposed affordable housing at the site, in studios through three bedrooms, with delivery tied to funding availability. It records the Fall 2025 cost reductions that lowered the amount of housing the project could carry, and the Board of Supervisors' unanimous approval of the project on 24 March 2026.
The design also carries ground-floor public restrooms, community-accessible meeting space, public art and two retail spaces.