On rainy days, the predominant sound in San Francisco’s Central Subway is running water. Occasionally, the steady gurgling is interrupted by announcements and the rumbling of light rail vehicles.
On the boarding platform of Chinatown-Rose Pak Station last Thursday, 100 feet underground, a steady stream of water fell from the ceiling onto the tracks and walkway, some captured in two buckets surrounded by orange safety cones. It smelled of sulfur, and the nearby wall was damp and coated in a residue apparently left behind by a trickle.
Water pooled in the trackway, and ceiling panels were missing over the platform. One section of tracks was visibly rusty. A bug zapper hung from a wall by an empty chair, apparently to kill insects attracted by the swampy conditions. More water pooled in the glass-encased elevator shaft.
“Leaks are everywhere,” said a station agent who asked not to be named because he was not authorized to speak to the press by his bosses at the San Francisco Municipal Transportation Agency.
Ed Siu of the Chinatown Merchants United Association said his members have been asking the SFMTA to fix the leaks for the last 16 months.
“It’s totally ridiculous,” Siu said. “It’s brand new. We spent a lot of tax money for it.”
The $1.9 billion, 1.7-mile-long Central Subway was San Francisco’s first new subway in more than 40 years. The project arrived four years late and hundreds of millions of dollars over budget.
When it officially opened in January 2023, extending the T-Third Street line from Bayview to Chinatown, the transportation agency touted it as a way to provide “faster, smoother transit service between some of the city’s busiest, most vibrant areas.” But last August, a leak at the Chinatown-Rose Pak Station forced the closure of the main stairwell from the concourse level to the platform, inconveniencing riders. Officials said the leaks would take at least six months to fix. Eight months later, the cash-strapped agency is still working out repair plans.
However, internal emails between SFMTA staff and consultants reveal that there are persistent leaks throughout the subway and its three subterranean stations.
Containing the leaks
The Chinatown-Rose Pak Station was a complicated engineering problem from the start because the water table in the area is very high and the station itself is very deep.
To deal with this, dewatering wells were used to lower the water table so the station could be built with a waterproof membrane wrapped around it.
But water has risen to the top of the station’s main cavern and begun to enter at construction joints, according to an Aug. 8 internal presentation on the leaks by SFMTA Deputy Director of Maintenance of Way Terrance Fahey. There are spaces between the “water stops”—devices that wick the water away—at construction joints and the waterproofing membrane.
“Beyond concerns for patrons slipping on the terrazzo flooring, water seepage in the long run will start corroding fasteners holding up the glass fiber-reinforced concrete panels, steel conduit and concrete reinforcement,” Fahey’s presentation warned.
In emails, staff wrote that leaks have emerged in back-of-house rooms: The platform elevator shaft area on Aug. 8, 2023, the fan room on Oct. 8, 2023, and the air conditioning room on Jan. 4 of this year.
The subway does have a drainage system that allows water to run out of the tunnel, “but the leaks that we’re trying to address are on the roof of the tunnel,” transportation agency spokesperson Michael Roccaforte said. “The system for water mitigation helps contain the leaks and run the water through pipes out to the sewer.”
BART owns and manages much of the Muni Metro. Its tunnel between Embarcadero and 16th Street Mission stations is below the water table, meaning either seawater or freshwater is constantly a threat. BART’s maintenance crews are said to call the stretch of trackway “the rainforest.”
“BART has leaks. But they have a budget, staff and plan; they address it, and they fix it,” said Nadeem Tahir, the Central Subway’s former project director. “This is all new for SFMTA. They need to fix the leaks that are there, make a long-term plan and then execute. They’ve hired some of the best experts. Unfortunately, SFMTA had to wait to find the cash. Otherwise, this work would have been done a long time ago.”
The Central Subway tunnel was built with special holes for grout to be repeatedly injected over it to seal it. Think of it like a roof that needs to be rebuilt as it periodically gets washed away.
“It will take time and effort to fill voids with grout and isolate areas that are leaking until we can finally plug them,” Fahey wrote in his presentation.
Water intrusion even cost the SFMTA two retail leases to Dragon City Inc.—the business behind AA Bakery and Cafe on Stockton Street. Henry Chan, the owner, said he was frustrated by the situation, but understood the necessity of the repairs.
The retail spaces “are unavailable for leasing by a long-term tenant until at least 12 months after the water mitigation is completed and tenant improvements are done,” Roccaforte said.
In the meantime, the spaces are being used for short-term pop-up stores.
'Hydrological puzzle'
Daily weekday ridership for the T Third averaged about 14,300 in 2023, way below the 43,000 riders SFMTA expects by 2030. (Last month it had 17,300 weekday ridership.) Also last year, the Chinatown-Rose Pak Station averages 1,250 daily weekday entries, the Union Square/Market Street station gets 1,110 and the Yerba Buena/Moscone Station gets just 350. Plugging the leaks for this small group of passengers will cost millions.
The SFMTA’s Transportation Capital Committee budgeted $7 million for the subway leaks and expects to spend $4.5 million on Chinatown-Rose Pak Station.
“We will present the water mitigation contract to the SFMTA Board of Directors once it is ready to be issued and repairs are anticipated to take six months,” Roccaforte said. “Improvements and repairs for the Central Subway are being paid for by the SFMTA using local sources, with federal funding running out a few years ago.”
The subway was largely funded by the Federal Transit Administration, whose regional office is working with SFMTA on all administrative requirements to close out the grants for the project, according to a FTA spokesperson.
The agency is working with Gall Zeidler on the water mitigation plan "as part of the remaining repairs and improvements for the Central Subway," Roccaforte said. "We’re working with them because of their experience and expertise, as this specific issue requires some specialization since the leaks are not at a fixed location."
Aaron Peskin, president of the Board of Supervisors who represents Chinatown, said he’s been keeping tabs on the leaks since before the line even opened.
“They have dealt with some of the problem, but not all of the problem,” Peskin said. “It's a complex hydrological puzzle to solve, and they're working on it. But it obviously comes with unfortunate impacts—including the impacts to the leaseholders.
“It's not free,” Peskin added. “It comes with expenses and part of the cost of running the new subway.”
Update: The ridership figures for the T-Third Street light rail line have been updated.