Butter is a much-maligned food these days in the bayside town of Marshall.
At Tony’s Seafood Restaurant, diners will notice a conspicuous lack of the familiar ramekin of the deliciously fatty yellow bovine product alongside their sourdough. If requested politely, the staff may bring some out from the back—reluctantly.
This modest change is part of a larger effort by Marshall restaurants to reconsider how they handle fats, oils and grease, which are contributing to a costly buildup in the town’s shared wastewater system.
The Marshall community wastewater system, a $3.2 million project built in two phases in 2007 and 2014, connects 60 homes and two restaurants along the east shore of Tomales Bay.
Sewage travels through a pressurized 5,300-foot pipeline to a pretreatment facility before dispersing into a leach field on a six-acre parcel behind the Marshall Post Office, on the Barinaga Ranch. Homeowners support the system with annual fees, currently set at $1,432 per residence, which contribute to a fund managed by the county.
When fat, oil and grease—known in the wastewater industry as FOG—are washed down the drain, they eventually cool and harden. Over time, they collect on the sides of pipes and on filters, impeding water flow through the vast arterial underground networks.
For those tasked with maintaining these networks, grease is not just the word—it’s also their bête noir.
“We’re system operators, we’re not grease trap experts, but I know that there is a problem just based on what I’m seeing coming into the system,” said Brandon Jacka, the West Coast operations manager for Natural Systems Utilities, the company contracted to maintain the system. He addressed a circle of concerned residents during a mid-October meeting held at the Lodge at Marconi.
After a routine inspection in the spring, Mr. Jacka’s team found enough grease buildup to recommend replacing the filters, saddling the community with a nearly $32,000 bill, or $541 per household.
The discovery of the filter replacement cost buried in the minutes of a Board of Supervisors meeting ignited frustration among residents who felt blindsided.
“It seems that the county may be failing to meet its fiduciary duties,” a group of citizens wrote in a July letter to the county. They said residential users appeared to be subsidizing the grease problem caused by the restaurants.
Residents are growing increasingly frustrated by the opacity of their wastewater fund. They have little sense of its current balance and how much has been siphoned off for upkeep and repairs.
“Since this system has never had any issues before, there is a reserve,” Arti Kundu, a staffer with Marin County’s Environmental Health Services who manages the fund, said at the October meeting. She estimated the fund to be at “about $90,000.”
In recent correspondence with the Light, however, Ms. Kundu said that approximately $65,000 had already been spent, promising a more comprehensive update on the fund by year’s end.
The county has since determined that replacing the filters is not immediately necessary. Instead, it enlisted City Sewer Pumping, a family-owned business in Point Reyes Station, to perform an extensive cleaning of the treatment system and leach field.
In late October, technicians used a vacuum wand to slurp up the thick, grayish grease. A high-pressure hose flushed the network of pipes that channels waste to the gravel field and purged layers of fermented sludge from the system’s filtration fabric.
Still, questions linger about who should shoulder the cost. “If the cleaning is due to grease, and if the grease is coming from specific sources, why should all households pay for it?” one resident asked Ms. Kundu during the meeting.
“Socialism!” another quipped.
Tony’s Seafood and the Marshall Store, the two businesses tied to the wastewater system, are beloved institutions renowned for their fish and chips, clam chowder, po’ boys, fried oysters and bivalves grilled in garlic butter. But all of these delicacies beget towers of plates, pots and pans that glisten with the day’s accumulation of oil and grease.
As part of their standard protocols, the restaurants pour cooled oil and scrape congealed fat into barrels for collection. Range hood filters are now removed and cleaned offsite, and kitchen floors—often slick in a layer of grease from searing, sautéing, caramelizing and frying—are routinely mopped, with the resulting bucket of iridescent greywater carefully discarded.
At Tony’s, a recent discovery revealed that the mop sink’s piping entirely bypassed the grease trap, a 2,000-gallon tank that separates oil, water and food particles through the simple mechanics of density. Fats float to the top, while grease-free wastewater continues through the interceptor and into the system. The restaurant is now rerouting the sink’s drainage to flow through the trap.
These challenges are part of the infrastructure inherited by the restaurant’s current owners when they took over the 77-year-old establishment. “We want a system that works and are exploring every solution,” said Terry Sawyer, co-owner of Hog Island Oyster Company, which owns Tony’s. “But these are issues every restaurant in West Marin faces. What’s the answer—stop eating french fries?”
To mitigate the problem, the county has mandated that the restaurants pump and clean their grease traps and septic tanks weekly instead of monthly. Staff have been trained in stricter disposal practices. Weekly FOG tests conducted at both establishments aim to ensure that grease levels in wastewater samples remain below 100 milligrams per liter. Recent results have been variable—Tony’s failed four out of nine tests, while the Marshall Store failed five out of nine.
These measures, ongoing since the summer, have been costly for the restaurants, adding between $10,000 and $15,000 to their monthly overhead.
When Tony’s joined the wastewater system in 2014, it was a modest weekend-only operation. At the time, its daily wastewater flow was capped at 1,200 gallons. But since Hog Island acquired it in 2017, the restaurant has expanded to six days a week, often exceeding its flow allocation. Recent reports indicate that flow limits were exceeded multiple times in a single quarter, with flows reaching as high as 2,900 gallons per day.
“The system wasn’t designed to process the levels of oil and grease that it’s currently seeing,” said Norm Hantzsche, the Questa engineer who designed the wastewater system. “The original design at Tony’s was for the prior operation, which was weekends only. You’d have the big surges on the weekend, which would fill the tank. Then during the week, there would be a time for settling, cooling, and it probably worked more effectively under that historical condition.”
Mr. Sawyer noted that his company’s other locations, in Larkspur and Petaluma, which have smaller in-ground grease traps and handle more customers, do not face these issues, suggesting they may have other causes.
The communal wastewater system in Marshall was established after septic systems on the east shore came under scrutiny from state health officials in the late 1990s. In 1998, 171 people became ill after consuming oysters grown in the bay. Health officials traced the norovirus outbreak to failing septic systems, leading to a three-month closure of the oyster farms. Many of the narrow lots sandwiched between Highway 1 and Tomales Bay lack sufficient space for individual leach fields, and the soil—often shallow and sandy—is unsuitable for traditional septic solutions, which require several feet of buffering soil above and below.
The system was hailed as a major success, heralding the end of wastewater woes for Marshall. Other towns like Woodacre are looking to it as a model, with representatives touring the facility as recently as last December.
At the Marshall Store, a question that lingers for owner Shannon Gregory is, “Why is this happening now after 18 years?”
But the answer may be simple. Flows at the restaurants have tripled since 2022, according to Mr. Jacka, the system’s operator, and testing for oil and grease only began this year. Previously, monthly system checkups sufficed, but escalating issues now require his team to visit Marshall several times a week.
“Right now, the system doesn’t meet compliance,” he said. “I’m having to constantly explain to the state why the system is failing.” He recently gave a tour of the facility to engineers from the San Francisco Regional Water Quality Control Board, who are concerned about the regulatory shortcomings.
For some, including Mr. Gregory, the underlying problem remains elusive. “We haven’t changed our menus, and our capacity hasn’t changed much,” he said. “It seems like there is something odd going on. Soup and salads and sandwiches—we barely use any grease at all.”