Woodacre and San Geronimo may finally join their more developed neighbors over the hill in using a community sewer system rather than individual septic systems.
For more than a decade, a group of homeowners in the Woodacre Flats, which resembles the suburban neighborhoods of Fairfax and San Anselmo, has been pushing to end the area’s dependence on the aging systems that prevail in rural West Marin. They came close in 2017 when the county commissioned an environmental impact report for a planned wastewater treatment plant on the former San Geronimo Golf Course, but the county then sold the golf course property to the Trust for Public Land. With the trust disinterested in a treatment facility, the county was sent back at the drawing board.
Last Tuesday, supervisors approved $120,000 for a new feasibility study by the same firm, Questa Engineering Corporation, to study alternative solutions for wastewater treatment in Woodacre, including a community leach field and treatment facility on Fire Road. More than 90 percent of those funds were previously allotted for the 2017 environmental report.
“This is a commitment that the county made a long time ago,” Supervisor Dennis Rodoni said at last week’s meeting. “This is a much more focused study than the previous study.”
The idea for a community wastewater system in Woodacre is at least 15 years old and was sparked in part by bacterial monitoring conducted in the Tomales Bay watershed in 2004. Woodacre, with its high water table, clay soils and preponderance of 50-year-old redwood septic tanks, scored poorly for fecal indicator bacteria like E. coli. A voluntary survey found two thirds of the village’s septic systems were in bad shape, and a 2017 county study confirmed that failing septic systems continued to be a source of human fecal contaminants in Woodacre Creek.
Questa conducted its first study in 2011, initially raising Fire Road as a potential leach field location but then settling on the more ambitious golf course treatment plant. The plans had the support of the property owners at the time, but after the golf course changed hands, the plant was off the table.
“We are going to pick it up from what we did in 2011,” said Arti Kundu, a project manager with the county’s Environmental Health Services division.
In the new study, which will be finished by June 2023, Questa will survey Woodacre and San Geronimo residents to help define a service area for the system, determine the system’s capacity and devise alternatives. Those could include individual onsite septic upgrades overseen by a local management district, the leach field on Fire Road, and a separate wastewater treatment plant with varying capabilities. In the most advanced alternative, the water would undergo high-level treatment so that it could be used to recharge aquifers or irrigate neighboring pastures, open space or gardens.
“We’re open to any alternative, because we really want to solve these issues,” said Christin Anderson, a member of the Woodacre and San Geronimo Flats Wastewater Group, which first pushed the county to study the system. On days with heavy rain, water pools on the ground around Ms. Anderson’s house in the Woodacre Flats, she smells sewage outside, and her neighbors’ tubs and sinks back up.
The county’s environmental health division has no information on 30 percent of Marin’s roughly 8,000 septic systems, many of which were built before current code requirements and are likely failing or flawed. This is especially concerning in relatively dense communities that sit on high water tables or near creeks, where fecal contaminants can easily seep into the groundwater or reach the bay and ocean. The Woodacre Flats surround Woodacre Creek, which quickly drains into San Geronimo Creek, a tributary of Tomales Bay.
Ms. Anderson sees a model in Marshall, where many homes sit directly on the bay, very near oyster beds. In 2007, concern over sewage contaminating shellfish sparked the community to partner with the county on a system that pumps waste from 50 homes to a reliable pre-treatment unit and leach field on a hillside ranch. Property owners pay an annual fee with their property taxes that covers the system’s operation. Questa engineers will consider AdvanTex, the treatment system used by Marshall, for the Woodacre area.
Yet the widespread use of septic systems—along with zoning and land-use restrictions—is among the factors that keep West Marin sparsely developed. Septic tanks have limited capacities, and upgrades are expensive. Fears of unchecked development have cropped up every time one of the region’s communities floats the possibility of a community sewer. In 2019, the Point Reyes Station Village Association pushed back on a suggested feasibility study for a community system, something the town had already nixed when it was suggested by the United States Coast Guard in 1989.
The proposed system has its own critics. Members of the San Geronimo Planning Group opposed the earlier E.I.R., questioning its necessity and raising fears of oversized homes. “It was supposed to help people in the Woodacre community, and then it just got larger and larger,” planning group chair Eric Morey said of the golf course concept. “It was out of control.”
Mr. Morey said the leach field on Fire Road was a better idea, but he wasn’t convinced it was necessary. He cited a study his group commissioned that found fecal contamination in Forest Knolls’s Montezuma Creek was worse than in Woodacre Creek. And the community system wouldn’t fill any housing needs, he argued.
“This is just going to allow people to increase the size of their homes,” he said. “It’s not really going to increase affordable housing in the valley.”
But Ms. Anderson cautioned against relying on the status quo of environmentally unsound septic systems to discourage building. “We don’t want to control development with broken septic systems,” she said. “There are so many other ways to control development.” What’s more, she said, the constraint doesn’t apply to the very rich: If you can afford an expensive, high-capacity septic system, you are free to build a larger home.
Sarah Jones, the assistant director of the county’s Community Development Agency, pointed out that the project has no direct goals related to expanding housing, affordable or otherwise. The system wouldn’t be designed to accommodate any parcels that remain undeveloped.
“It wouldn’t enable growth, it’s meant to solve the problem of the existing properties,” she said. But by removing a problem—failing septic systems—that forces many homeowners to avoid seeking building permits, the county could alleviate the degradation of its existing housing supply, Ms. Jones said.
Questa’s 2017 study considered a service area that would have included more than 350 homes along San Geronimo Valley Drive and Meadow Way in San Geronimo and in the “flats” of Woodacre’s Central Avenue, Railroad Avenue, Redwood Drive, Castle Rock Avenue, Taylor Avenue, Park Street, Scott Street, Crescent Drive, Elm Avenue and Oak Grove Avenue. The service area in the new study remains to be defined.
Mr. Morey, who lives in the hills of Woodacre, said his immediate neighborhood also has failing septic systems. He believes the county should work individually with homeowners to fix them, rather than prioritize one neighborhood over another for a community system.
Yet the situation in the flats is especially dire, and Ms. Anderson said a community system will be cheaper for homeowners than trying to make repairs on their own. “If we pitch in together,” she said, “it will be affordable.”