In Alamo, No Ordinance Requires a Septic Inspection Before You Sell. Escrow Still Does.

"Central San does not have a point of sale sewer lateral inspection ordinance." That's the exact line on the district's own FAQ page, and it catches a lot of Alamo sellers off guard, because they assumed Contra Costa County treated septic and sewer inspections the way several other California counties do: as a legal condition of transferring title. It doesn't. Santa Cruz County has required a septic inspection and pumping report before closing since July 2023. Contra Costa County has no equivalent rule. And yet nearly every Alamo listing on a septic system still gets an inspection, because the lender asks for one, not the county.

That gap between what's legally required and what's practically expected is the first thing worth understanding about selling a home on septic or well in Alamo. The second is where the paperwork actually goes once you start asking questions, because Alamo doesn't have a city hall to ask.

No City Hall Means Every Answer Comes From Martinez or Concord

Alamo is unincorporated. Land use decisions run through Contra Costa County's Department of Conservation and Development, and the Alamo Municipal Advisory Council can weigh in on neighborhood concerns but doesn't issue permits, doesn't approve septic plans, and doesn't process a building application. Anyone used to calling a town planning office in nearby Danville will find the routing different here.

Two county offices carry most of the load. Contra Costa County's Environmental Health division, which reviews septic and well plans, sits at 2120 Diamond Blvd, Suite 200, in Concord, and can be reached at 925-608-5500. General building and planning applications, including anything involving an ADU, go through the county's Application and Permit Center at 30 Muir Road in Martinez. Neither office is in Alamo, and they aren't the same department.

That distance matters when a listing is moving. A septic inspection report and a well's bacteriological test come from Environmental Health's own files, separate from whatever a structural home inspector pulls together. Requesting them means a call to a county department many sellers have never had reason to contact before, not a quick lookup on a city website.

What the County Actually Regulates, and What It Leaves to the Market

Contra Costa's rules get specific on construction. The minimum separation between a well and a septic tank or leach field is 100 feet, and any addition to a home on septic needs Environmental Health's review before a building permit gets issued. What the county doesn't do is dictate the terms of a private sale. There's no inspection deadline, no county-mandated septic disclosure form beyond the state's standard Transfer Disclosure Statement, and no sign-off required to close escrow on an existing system that isn't being altered.

That's the space lenders fill. Most conventional, FHA, and VA underwriters won't fund a purchase on a septic system without a current inspection report, which turns a county non-requirement into a de facto industry standard. Sellers who read "the county doesn't require it" as "I don't need to worry about it" tend to be the ones scheduling an inspection mid-escrow instead of before listing, on a market where the clock is already tight.

Where the Money Actually Moves

For anyone weighing whether to leave septic behind entirely, Central Contra Costa Sanitary District runs a Septic-to-Sewer financing program that covers Alamo along with Danville, Lafayette, Moraga, Orinda, Pleasant Hill, Walnut Creek, and parts of Martinez and San Ramon. It doesn't waive the cost of connecting. It spreads it out.

EBMUD's separate capacity charge for a new water meter runs roughly $19,500, which matters for anyone adding an ADU that requires its own connection. An ADU tied to the existing house meter avoids that charge entirely, which is one more reason the septic-versus-sewer question shapes an addition's design before it shapes its square footage.

The 2025 Rule Changes That Landed on Top of All This

Two changes from 2025 reshaped what an Alamo property on septic can actually do.

In May 2025 the county rewrote its ADU ordinance. On lots of 12,000 square feet or more, which covers nearly every conventionally zoned lot in Alamo, a detached ADU can now run up to 1,200 square feet, an attached garage of 600 to 800 square feet doesn't count against that limit, and the old requirement that an ADU architecturally match the main house is gone. None of that removes the septic question. Whether a lot is on septic or sewer still determines what Environmental Health will approve, alongside where creeks, protected oaks, and slope sit on the parcel.

Separately, the San Ramon Valley Fire Protection District, which handles fire review for new residential construction in Alamo, now works from 2025 state fire-hazard maps that place parts of the district, including Alamo's hillside edges toward Las Trampas and the Diablo foothills, in elevated severity zones. New construction in those areas needs ignition-resistant materials and defensible space, and the fire district signs off before final inspection, not after.

Neither change is disqualifying for a typical remodel or addition. Both mean a septic upgrade, an ADU, or a construction project that used to be a straightforward county process now carries an extra review step depending on exactly where the parcel sits.

What This Costs You in a Market Moving This Fast

Alamo's median sale price reached $3,110,442 in August 2026, up 24.5 percent from a year earlier. Listings that closed in September 2026 spent a median of 37 days on the market, 26 percent faster than the same month in 2025. In a market compressing that quickly, the sellers who lose leverage usually aren't the ones with septic problems. They're the ones who discover mid-escrow that a county-approved lab needs two weeks to schedule an inspection, while a buyer's lender clock keeps running regardless.

Ordering the inspection before listing, not after an offer arrives, turns a county non-requirement into documentation a buyer's lender can act on immediately instead of a scramble that stalls closing.

FAQ

Does Alamo require a septic inspection before I can sell my home? No county ordinance requires it. Contra Costa County's Environmental Health division regulates septic and well construction, but there's no point of sale inspection mandate the way Santa Cruz County has had since 2023. Lenders are the ones who typically require a current inspection before funding a purchase.

Where do I go to pull septic or well records for an Alamo property? Contra Costa County Environmental Health, at 2120 Diamond Blvd, Suite 200, in Concord, maintains septic and well plan files. General building and planning permits, including ADUs, run through the county's Application and Permit Center at 30 Muir Road in Martinez.

Does converting from septic to sewer make sense before selling? It depends on timeline and budget. Central San's Septic-to-Sewer program serves Alamo with connection fees currently running $9,200 to $10,200 per unit, financeable through the property tax bill, but the physical sewer line work is a separate direct cost to the owner and the process rarely fits inside a typical escrow window.

If your Alamo property runs on septic or well and you're weighing a sale this fall, Jeff Snell can walk through what your specific parcel's inspection and permitting timeline looks like before you list, not after an offer is already on the table.