Victoria Sanchez shows photos of a flood on Cayuga Avenue in San Francisco on Nov. 28, 2022. (Beth LaBerge/KQED)
Months before this fall's rains began, Victoria Sanchez stood out in front of her home on Cayuga Avenue in San Francisco’s Mission Terrace neighborhood. Her block appeared ordinary on that July day: rows of colorful Mediterranean-style homes stretched wall-to-wall as the 44 Muni bus rumbled past the corner.
The scene was typical of many neighborhoods across San Francisco with one distinct difference. Along the sidewalks and driveways of Cayuga Avenue lay rows of sandbags, a reminder of the destructive floods of sewage and stormwater that the rainy season can bring — inundations that have ravaged the neighborhood for decades.
Sanchez walked her street with an album full of photographs and news clippings as she retold stories of the floods.
Pointing to one house, she recalled the death of her neighbor’s dog in 2004 when six feet of water poured into their garage shorting the electrical outlets. That family has since left the neighborhood.
The same 2004 flood devastated Sanchez’s home.
“I lost everything that was down in the basement,” Sanchez said. “My pictures, memories, things that I had from my kids, a sewing machine, everything that I had.”
The loss of irreplaceable items was only the start. The flooding damaged her home’s foundation, warped her garage door, left her drywall contaminated with mold, and flooded her backyard garden with residential, commercial and industrial waste.
“We didn’t have flood insurance because we couldn’t afford it,” said Sanchez’s daughter Maria. “The house’s foundation is still damaged to this day.”
Neighbors recounted similar experiences of a 2014 flood that once again inundated Mission Terrace homes and businesses with sewage.
“We are always on edge for the next rain,” Sanchez said. “Until this is fixed, the flooding will likely happen again.”
Mission Terrace isn't the only San Francisco neighborhood to suffer problems with destructive flooding that both residents and government agencies trace to the city's failure to upgrade sections of its sewer system.
Frustrated with the inaction by the San Francisco government, neighbors from several neighborhoods, including parts of the Mission and West Portal areas, have banded together in a campaign called Solutions Not Sandbags to demand action from the city.
Problems with the sewer system have also drawn the attention of state and federal regulators.
In 2021, the California Regional Water Quality Control Board issued a cleanup and abatement order, and the flooding prompted an order from the U.S. Environmental Protection Agency for the city to begin monitoring and reporting sewage overflows like the ones on Cayuga Avenue.
A review of hundreds of pages of court documents and studies, interviews with a dozen residents, experts and officials from multiple government agencies shows San Francisco has delayed upgrading sections of sewers that continue to cause damage to residents' property.
“This flooding isn't just rainwater,” said David Hooper, an advocate with Solutions Not Sandbags. “This is water mixed with sewage waste, this is contamination.”
Why it floods on Cayuga Avenue
Apart from some older sections of downtown Sacramento, San Francisco is the only California city served by a sewer system that collects both wastewater and stormwater in a single set of pipes.
When it rains, stormwater increases that flow dramatically, and city facilities collect and treat up to 500 million gallons a day.
Heavy rains can overwhelm the system, requiring excess flows of mixed sewage and stormwater to be discharged into nearby waters — something the SFPUC says happens about 10 times a year on average.
But sometimes those heavy flows hit bottlenecks in the system, forcing sewage up onto neighborhood streets before it can reach the discharge points.
One of the bottlenecks lies downstream of Cayuga Avenue, where a sewer main beneath Alemany Boulevard can't handle the volume of water that arrives during prolonged heavy rain.
Models created by the city's Public Works department show that a five-year storm — a storm with a 20% chance of occurring in any given year — will trigger flows that exceed the capacity of the pipe beneath the boulevard and lead to flooding of Lower Alemany and along Cayuga Avenue.
Cayuga's geographic setting is also a problem. The street runs downhill along the course of a natural stream. The lower, eastern end of the street butts up against Interstate 280 — which essentially acts as a dam to water flowing down the street. When the Alemany sewer main backs up, the lack of drainage further complicates the flooding in the area.
“Initially the Public Utilities Commission's argument was that it's the watershed causing the flooding, claiming that more green infrastructure will solve the problem,” said Lisa Dunseth, an advocate of Solutions Not Sandbags. “The problem is actually a structural engineering issue where the sewers are too small. And they knew it. And it's been that way for over 50 years.”
In fact, problems with sewer capacity downstream of the Mission Terrace neighborhood were known more than 50 years ago.
In 1964, a project to enlarge a section of the sewer along lower Alemany Boulevard was listed as one of dozens of projects that might benefit from a bond issue on the city's June ballot. The bond passed, but the sewer improvements never materialized.
Throughout the 1970s, improvements in the area were sidelined as the city invested in higher-priority projects to comply with new requirements enacted by the federal Clean Water Act.
In 2009 — five years after the flooding that beset Cayuga Avenue and destroyed Victoria Sanchez's belongings — the SFPUC commissioned a new analysis of the sewer system and suggested needed improvements.
The resulting 2010 Sewer System Master Plan acknowledged the sewer bottleneck problem in the neighborhood and proposed two possible solutions costing roughly $250 million according to documents. A less costly “eastward solution” proposed building a 6,000-foot auxiliary sewer under Alemany Boulevard to aid in handling high flows during rain events, while the preferred “westward” solution recommended constructing a relief sewer that would route flow from the Cayuga area to terminate at Ocean Beach.
The 2010 Sewer System Master Plan evolved into the 2012 Sewer System Improvement Project in which the Lower Alemany solutions were not included due to “budget constraints and a desire to evaluate an integrated approach to Lower Alemany including gray and green infrastructure,” according to a statement from the SFPUC.
The continued inaction has led to further flooding and subsequent damage of residents' homes in recent years. Nancy Huff and Bob Popko, who bought their house on Cotter Street in the Mission Terrace neighborhood in 2012, recounted a flood that occurred in 2014.
“We lost boxes and boxes of old childhood photographs. Things that were irreplaceable were just totally gone,” Huff said. “We had to replace the downstairs bathroom that had just been put in within less than a year. We had to cut out the damaged drywall, the tiling was ruined. It all had to be replaced because it just wouldn’t dry.”
After the 2014 flood, some Mission Terrace residents filed suit against the city and began demanding answers from officials at public meetings.
“The city was not responsive,” said Huff. “That is why there have been two lawsuits from this neighborhood against the city, both of which the city lost. We had the SFPUC and [former SFPUC Director] Harlan Kelly on our street over and over and over again, and they were just very hand-wavy and noncommittal on the issue.”
In 2018, eight years after the publication of the Sewer System Master Plan that identified needed improvements, the SFPUC included the Lower Alemany area into the Sewer System Improvement Plan.
“It's kind of sad to me that San Francisco is not helping its residents, because we do pay property taxes like everyone else,” said Maria Sanchez.
State and federal regulators step in
The Clean Water Act requires cities to maintain a National Pollution Discharge Elimination System permit, which outlines the conditions under which pollutants can be released into waters under federal jurisdiction.
NPDES permits must be renewed every five years, and in 2019 San Francisco challenged new requirements added to its Oceanside Treatment Plant permit.
According to a requirement in the new permit, San Francisco would have to report discharges at any point of the sewer system, not just from outfalls along the coast.
In 2020, the EPA’s Environmental Appeals Board denied San Francisco’s challenges to the new permit. In a decision denying review, the board said the new reporting requirement is "an appropriate mechanism … to determine whether the permitted combined sewer system is operating in compliance with the permit, including the requirement to maximize storage without increasing upstream flooding into basements and streets, which can negatively impact human health and the environment.”
The new permit is currently on hold pending a city appeal to the U.S. Ninth Circuit Court of Appeals.
Amid the city's wrangling with the EPA, the regional branch of the state's water quality agency also got involved in the issue of overflowing sewers. Under an agreement hammered out last year, the city will comply with an order from the San Francisco Regional Water Quality Control Board to address flooding issues in three neighborhoods.
The order requires the city to invest up to $600 million to fix the chronic overflow problems near 15th Avenue and Wawona Street in the city's West Portal neighborhood, 17th and Folsom in the Mission and Lower Alemany downstream of Cayuga Avenue.
The project to address flooding in West Portal broke ground last year, with an estimated completion date of spring 2024.
The projects to remedy flooding at 17th and Folsom and Lower Alemany are still in the planning phases.
“The settlement will also allow the city one year to assess alternative designs for the projects that will benefit the Folsom and Lower Alemany neighborhoods,” said Joseph Sweiss, SFPUC press secretary. “Potential approaches involve both traditional capacity improvements and surface improvements, such as green infrastructure.”
During the SFPUC commission meeting on April 12, documents were presented outlining the potential solutions to address the flooding in the Lower Alemany and Cayuga areas.
The Alemany auxiliary solution, which was first proposed in the 1964 bond measure and then again in the 2010 Sewer System Master Plan, would install 6,000 feet of a 10-foot diameter pipe to alleviate pressure on the Alemany sewer.
Documents show that design completion for the Lower Alemany project is forecast for July 2024. The project is forecast to be complete in March 2028.
Still, residents of Mission Terrace are skeptical given the city’s track record with large capital improvement projects.
“If you look at Van Ness [rapid bus project], if you look at the Central Subway, construction on both projects were way over budget and years out of date,” Hooper said.
The SFPUC acknowledges that the sewer improvements will take time.
“Since these complex and large-scale capital projects take years, the SFPUC provides support and resources tailored to these neighborhoods, including but not limited to flood insurance resources, free sandbags coordinated and delivered to these residents, and expanded stormwater grants up to $100,000 to upgrade properties for stronger resilience and flood prevention measures,” said Sweiss.
And while this is good news for many residents, it is also frustrating that it has taken this long.
“Sandbags aren’t the answer. The Public Utilities Commission has given us the runaround time and time again, it took the State to step in to solve an issue that has been ongoing for decades,” said Dunseth of Solutions Not Sandbags.
For residents in Mission Terrace who sit in homes fortified by rows of sandbags anxiously anticipating the next rain, it's now become a waiting game. Will the Alemany sewer, which the city has delayed upgrading for decades, be fixed in time to prevent yet another flood?
“It’s a hard issue of waiting until things settle down with the court system and planning and everything that goes on with that,” said Maria Sanchez. “While in the meantime, we have to sit here in a house that's pretty much falling down because they can't get their s--- together.”