West Marin’s housing crisis, and the future of affordable homes, may hinge on something as basic—and bureaucratically fraught—as septic systems.
In a county historically resistant to new development, zoning laws combined with stringent rules around wastewater management pose a formidable obstacle to construction.
Such is the case in Forest Knolls, where a property acquired by the Two Valleys Community Land Trust was intended to be a pilot project for transforming the area’s aging housing stock into multi-family affordable units. But after a year and a half of wrangling with septic regulations, the trust has put the property back on the market.
“This was supposed to be our proof of concept that affordable housing can be built here,” said Hal Russek, the land trust’s executive director. “What kind of message does this send about the feasibility of this kind of project?”
Land trusts like the T.V.C.L.T. play a key role in creating affordable housing by developing or renovating homes to offer at below-market rates. The trust, which operates 20 mobile homes in Forest Knolls and six senior homes in San Geronimo, purchased 6956 Sir Francis Drake Boulevard in March 2023 for $850,000.
The three-bedroom house, built in 1924, had fallen into disrepair. The plan was to convert it into three separate units—a one-bedroom accessory dwelling unit on the lower level, and a studio and a three-bedroom apartment upstairs—without expanding its footprint.
The trust allocated $450,000 sourced from a mix of grants and loans to cover cleanup and construction costs and replace the failed septic system, which had required frequent pumping.
West Marin is rife with similarly decrepit septic systems that owners are reluctant to upgrade due to the cost and regulatory complexity, said Pam Dorr, a former executive director of CLAM and the vice president of home preservation for Habitat for Humanity. A new septic system can cost from $60,000 to $120,000.
“These systems go unrepaired, and untreated waste leaks into our sensitive habitats,” she said.
For Ms. Dorr, the long-term solution lies in a comprehensive sewer plan, but short-term regulatory fixes are also needed.
The T.V.C.L.T. found that navigating county regulations was a labyrinthine process—and one that exposed the lack of a coordinated strategy to effectively support affordable housing projects.
In April 2023, the county’s Environmental Health Services division conducted an initial site review that raised concerns about the property’s proximity to a seasonal creek. A stream conservation area ordinance that applies uniquely to the San Geronimo Valley mandates a 100-foot setback from creeks and tributaries—significantly more than the 50-foot setback typically required for other waterways. A detailed study was ordered to determine the riparian edge.
The land trust was left in limbo for months before the county finally instructed it to submit a preliminary septic system plan for review.
In early 2024, the county confirmed that the property indeed fell within the S.C.A. And another new complication had emerged: The county discovered that the home was permitted as a two-bedroom dwelling, meaning the septic system could only support two to three bedrooms, not the five needed to make the project viable.
The land trust and its engineers went back to the drawing board, this time proposing an upgraded Class II septic system that would operate within the current system’s capacity of 450 gallons a day. The shift meant the project could be classified as a repair rather than new construction.
But months of negotiation yielded little progress. The revised septic plan, which included calculations to show how four or five bedrooms could be accommodated within the 450-gallon-per-day allowance, has received no formal decision from the county. Facing the gantlet of county approval, the trust decided it could no longer afford to wait. It listed the property last week for $1,150,000.
Septic system designs are generally based on a conservative estimate of 150 gallons per day per bedroom, which assumes full-flow fixtures and two occupants per room. Although county code allows for a 30 percent reduction for homes using water-saving technologies, this reduction is still insufficient, said Noadiah Eckman, a geologist who consulted on the Forest Knolls project.
In fact, Mr. Eckman was hired by the county in 2020 to study septic systems in unincorporated Marin. Recommendations from the resulting report were passed from the county to the San Francisco Bay Regional Water Quality Control Board, where it has been mired in review since 2021.
The study notes that actual wastewater usage in the area consistently falls below these outdated design standards. “We’re using systems that are oversized, far larger than what’s needed, and unnecessarily expensive,” Mr. Eckman said.
His recommondations include amendments to county septic regulations that could help pave the way for more affordable housing development.
From the county’s perspective, the decision on 6956 Sir Francis Drake was straightforward. “For this parcel, there was an attempt to work with a repair instead of a complete rebuild to a new septic system,” said Chris Choo, assistant director of the Community Development Agency. “A repair is a faster, easier option but doesn’t allow for increasing bedrooms.”
Mr. Eckman sees this as a catch-22, emblematic of a deeper misalignment in the county’s approach: Though new construction is required to increase septic capacity, the S.C.A. ordinance blocks new construction near San Geronimo and Lagunitas Creeks and their tributaries.
This bureaucratic quagmire is nothing new. “Septic regulations have been used for the past 50 years to limit development,” said Kit Krauss, board chair of the T.V.C.L.T. “So now, as we need to build more houses, something has to change.”
The county enacted the S.C.A. ordinance in 2022 after a decade-long legal battle with the Salmon Protection and Watershed Network. The ordinance limits development along creeks to protect critical habitat for coho salmon and steelhead trout.
But for Mr. Krauss, “There’s a big gap between where the regs are, and where the regs could be while still preserving the watershed.”
The project’s failure is the latest turn in a long struggle over how much of the answer to the affordable housing crisis lies in rewriting rules to encourage building.
Over the past four decades, the San Geronimo Valley has witnessed a steep decline in both school-aged children and new housing. While the population has grown by 15 percent since the 1980s, the number of children under 5 has plummeted by 67 percent. Meanwhile, the population of residents over 65 has more than quadrupled, now making up a third of the valley’s inhabitants.
“Everything that really needs to happen in West Marin begins with building more housing,” Mr. Russek said. “We’re already seeing our community hollow out. Without affordable housing, we lose the multicultural, multigenerational fabric that makes a community thrive.”