A Bay Area environmental group has given notice this week that it intends to file a citizen lawsuit under the Clean Water Act against the San Francisco Public Utilities Commission on account of “mixed sewage and trash-filled urban runoff” that is discharged into San Francisco Bay during heavy rains.
According to San Francisco Baykeeper, a nonprofit organization that says its mission is “to hold polluters accountable and defend San Francisco Bay,” the annual discharges amount to 1.2 billion gallons, containing 6 percent, or 72 million gallons, of sewage.
The sewage is alleged to contain “feces, bacteria, viruses, chemicals, and trash.”
Baykeeper’s formal notice to the city Thursday covers 24 single-spaced pages with a dense and technical description of the issue. Boiled down, however, the nonprofit’s concern is fairly straightforward and, as Eric Buescher, managing attorney of Baykeeper says, “it’s definitely not a secret.”
Unlike all other cities in the area, San Francisco has a “combined” system that treats sewage (discharge from indoor plumbing) and stormwater (rain and storm flows).
The CPUC operates a group of facilities — referred to as the Bayside facilities — that serve the eastern side of the city. They include a water pollution control plant, a wastewater collection operation, 600 miles of pipe, and a score of pumping stations.
The Bayside facilities treat both sewage and stormwater before discharging them into Mission Creek and ultimately the Bay.
Buescher says there are benefits and detriments to a combined system. The benefit is that both flows are combined into a single flow and that flow is treated before being discharged into the Bay.
In other California coastal cities, the stormwater is not treated, so in that respect the San Francisco approach is better since stormwater can contain pollutants.
However, there is a downside.
When the system’s capacity is overloaded by intense storms, the excess flows are released without all the treatment they would ordinarily get. And because the combined system processes both sewage and stormwater, what is released contains sewage as well as stormwater.
Buescher said that the city’s system goes back at least as far as the 1990s and it always contemplated that there would be times of such overflow. The city’s permit also contemplates that it will happen. However, what is supposed to happen in that situation is that the excess flow gets “primary” treatment before discharge.
The primary treatment is that the water flows down under the streets to Mission Creek but before it gets there, it goes through a “transport storage box.” The theory is, according to Buescher, that “the giant box underground acts as a settling tank” where the “harmful and heavier material will drop out and won’t end up being discharged.”
For that to work, the water has to move slowly enough so there is time for the pollutants to fall out. But Buescher says, that isn’t what is happening. “The velocity and force of the discharge … is so high that any effect you get from that settling just vanishes because it scours everything back up, picks up stuff that had settled out, and carries it with it.”
Buescher said, “It looks like and sounds like you are at a waterfall.”
The result is that in the areas of discharge around Mission Creek, Baykeeper has found in the days after a storm that the levels of pollutants spike up well above levels potentially dangerous to people and remain that way for “two, three, four, or sometimes even five days.”
The notice includes pages of water quality readings (and several highly unpleasant photographs) alleged to support those claims.
Buescher said that some of the problem is a result of climate change that has delivered bigger and more frequent storms. In 2023, a year with intense rains, he said 2 billion gallons of flow was dumped in Mission Creek.
But the core problem, in his view, is not climate change, it is that the city system isn’t actually providing effective primary treatment of the excess flow and that is the reason Baykeeper intends to sue.
Selective representation?
John Cote of the SFPUC answered questions about the notice by focusing on the benefit side of the combined system.
Cote said the “combined system provides greater environmental benefits because it captures and treats most stormwater to the same high standards that apply to wastewater from homes and businesses before releasing it to the bay or ocean.”
Cote said that the discharge of excess flows is “authorized by our Environmental Protection Agency and Regional Water Board permits. The SFPUC’s extensive system of underground storage, transport, and treatment boxes minimizes the frequency and volume of these discharges.”
He added, “The system is specifically designed to prevent trash from escaping … The outfalls are equipped with baffle and weir systems designed to catch floatable trash and solids, which are ultimately sent to one of our treatment plants after stormwater flows subside.”
In Cote’s opinion, “Cherry-picking select information without conveying the whole picture doesn’t benefit the environment, policy makers, or the public.”
Mark Westlund, communications director at Baykeeper, fielded the question of whether it is safe to swim in the Bay.
He said, “in terms of swimming in the Bay, we always recommend waiting a few days after a storm.”