Tony's Seafood, the restaurant Hog Island Oyster Company took over on the Marshall shoreline in 2017, pays around $20,000 a year in a wastewater assessment that gets passed straight through the lease to Hog Island's CEO John Finger. That number doesn't show up on the dinner menu, and if Tony's Seafood were a house instead of a restaurant, it wouldn't show up on a listing sheet either. It would just arrive, eventually, as a line item nobody budgeted for.
That's the thing about wastewater in Marshall-Tomales. A view of the bay and a well-staged kitchen tell you nothing about what's happening underground, and right now, with Marin County in the middle of rewriting the rules that govern it, the gap between what a property looks like and what it actually costs to keep is wider than usual.
The patchwork under the water table
Most of West Marin runs on septic, not sewer. Up until now, county oversight of those systems has been what local reporting has called ad hoc. Older buildings got grandfathered in under whatever standard existed when they were built, while anyone doing new construction faces the current, costlier permitting process. That means two houses fifty feet apart on the same stretch of shoreline can be operating under two entirely different rulebooks, and the year a system was installed matters as much as the property's price tag.
Marshall is a partial exception, and an instructive one. Decades ago, the county stepped in with grants and low-interest loans to build a shared wastewater system for a cluster of shoreline properties. Effluent from those parcels runs through pipes under Highway 1 and up the hill to a seep field near a dairy, and the county administers the whole thing through property tax assessments rather than leaving each owner to manage a private tank. Tony's Seafood is one of the properties inside that assessment district, which is why its wastewater bill reads more like a utility charge than a maintenance surprise.
Not every West Marin address gets that predictability. Stinson Beach holds its own separate permit with the San Francisco Bay Regional Water Quality Control Board and manages its systems independently of the county. Everywhere else, including most of Tomales, Point Reyes Station, Inverness, and Bolinas, you're generally looking at an individual, privately owned system, permitted and inspected case by case, with no shared assessment and no shared seep field to spread the cost around.
A rulebook that isn't finished yet
Marin County has been trying to update its Local Agency Management Program, the document that governs how septic systems are inspected, permitted, and repaired, since 2014. County staff aimed to wrap up community outreach by June of this year and bring an updated program to the Board of Supervisors for approval this fall. If that timeline slips and the county doesn't get an approved program in place, it defaults to stricter, one-size-fits-all state regulations instead of the locally tailored version it's been trying to build.
That timing puts anyone closing on a Marshall-Tomales property this year in an unusual spot. The rules that will eventually govern inspection triggers, permitting standards, and repair requirements are still being negotiated at public meetings, not settled law. A property that clears today's informal standard may face a different bar once the Board of Supervisors votes, and a buyer doing due diligence this month is evaluating a moving target rather than a fixed one.
What actually governs your parcel
The honest answer to "what's the septic situation here" depends entirely on which of three regimes a given property falls under, and that's not something a sale price or square footage figure will tell you.
| Location | Who administers the system | What a buyer should check |
|---|---|---|
| Marshall shoreline, community system | Marin County, funded through a property tax assessment | Whether the parcel sits inside the assessment district and what the current annual charge runs |
| Stinson Beach | Managed under its own permit with the Regional Water Quality Control Board | Local district rules, which sit apart from the county's forthcoming program |
| Most other West Marin parcels (Tomales, Point Reyes Station, Inverness, Bolinas) | Individual private septic system, permitted by the county case by case | The age of the system and its permit history, since older systems were often grandfathered under standards that no longer apply |
A property inside the Marshall assessment district trades a predictable annual bill for less control over the system itself. A property on an independent private septic elsewhere in West Marin trades that predictability for more autonomy and, potentially, more exposure if the system was installed under an older, looser standard.
The backwards assumption about "grandfathered"
Here's where the common assumption gets it wrong. It's tempting to think a grandfathered, decades-old system is the safer bet, since it's already proven itself and isn't subject to the newer, stricter rules being written for future construction. Residents at recent county meetings described the opposite pattern: inspections tend to catch newer systems, the ones already built to more current standards, while older, potentially failing tanks go years without the same scrutiny. One resident described a leaking system that had been a known problem for at least a decade before anyone forced a fix.
That inversion matters most for exactly the kind of property Marshall-Tomales is known for: a cozy, long-owned cottage that's changed hands rarely, sitting on a septic system nobody has looked at closely in years because it never triggered an inspection. Tom McCafferty of the Community Land Trust Association of West Marin has raised a related concern on behalf of long-term owners, pointing out that full system replacements can be financially out of reach for seniors living on fixed incomes, which is precisely the profile of many long-term West Marin sellers handling an inherited or long-held family property.
Put plainly: the age and story of a house tells you almost nothing about the condition of what's buried beneath it, and in this particular market, the older the ownership history, the more reason there is to ask when the septic system was last actually inspected, not just when the house was last painted.
What buyers and sellers should actually do before closing
- Ask specifically which of the three regimes above applies to the parcel, not just whether it's "on septic." The answer changes what you're financially exposed to.
- If the property sits inside the Marshall assessment district, request the current annual assessment amount and confirm whether it transfers with the sale, since it's structured as a property tax assessment rather than a private utility bill.
- If the property is on an independent system anywhere else in West Marin, ask for its permit history and the date of its most recent inspection, especially if the house itself has been in the same family for decades.
- Sellers with a legacy system that hasn't been inspected in years may want to get ahead of a buyer's question rather than answer it mid-escrow, particularly given how uneven inspection enforcement has been on older systems.
- Anyone weighing new construction or an ADU on a West Marin parcel should budget for the current, costlier permitting standard, not the older, cheaper one a neighboring grandfathered system got to use.
Common questions
Does buying a Marshall property inside the community system mean I take on the assessment? Since the assessment is structured as a property tax charge rather than a private contract, it generally runs with the property. Confirm the current amount and district boundary before you write an offer.
If my parcel is on a private system, do the county's pending changes affect me at all? Yes. The Local Agency Management Program governs private, county-permitted systems throughout unincorporated West Marin, including inspection triggers and repair standards, which is exactly what's being renegotiated ahead of the fall vote.
When will the new rules actually take effect? County staff have targeted approval by the Board of Supervisors this fall, with implementation following in a second phase. Until that vote happens, the standards a property is held to remain in flux.
None of this is a reason to walk away from a bayside cottage or a bluff-top parcel. It's a reason to ask the right question before you fall for the view. Terry Donohue has spent decades walking this exact stretch of shoreline, coordinating the vendors and paperwork that come with legacy properties, probates, and the kind of complicated sale where the septic system matters as much as the setting. If you're weighing a purchase or a sale anywhere between Marshall and Tomales, call or text Terry before you make an offer, not after.