Why does a house that sells in three weeks sometimes take four months to actually close?
In South San Francisco right now, that question has a specific, unglamorous answer: the sewer lateral running from the house to the street. As of July 2026, single-family homes in the city closed at a median of $1,240,000, sellers walked away with 108% of their asking price, and the average sale took just 23 days to go from list to contract. Inventory sat at roughly 0.6 months of supply, which is another way of saying serious buyers had almost nothing to choose from. By every normal measure, this is a market that rewards speed.
But speed to contract is not the same as speed to close. Since June 21, 2022, South San Francisco has required every home sale to clear a private sewer lateral inspection before title can transfer, under an ordinance the city council passed that March. It is a step that has nothing to do with staging, pricing, or buyer demand, and everything to do with a pipe nobody sees until it's the reason a closing gets pushed.
An Ordinance That Looks Different Depending on Which City You're In
South San Francisco is one of seven cities in San Mateo County that require a compliance certificate before a home sale can close, alongside San Mateo, Burlingame, Hillsborough, San Bruno, Millbrae, and Pacifica. But "the seven cities require it" undersells how differently each one runs the process. Burlingame's version, under Sewer Lateral Test Ordinance 1329, requires a witnessed infiltration test rather than a video, meaning a city representative has to watch the test happen in real time. San Carlos, Belmont, and Brisbane only trigger an inspection when a homeowner pulls a remodel permit, not automatically at sale.
South San Francisco's rule, codified in Municipal Code Chapter 14.14, calls for a closed circuit television inspection performed by a licensed contractor, conducted in the presence of a city representative, with the resulting video submitted to Public Works for review. The city is checking for a specific list of defects: blockages, structural cracks, illicit connections, open joints, missing cleanouts, and pipe material that no longer has 25 years of useful life left in it. That last standard is the one worth sitting with, because it is also the standard most of the city's older housing stock cannot meet.
Why the 1950s Are the Real Variable Here
The ordinance did not appear out of nowhere. It exists because South San Francisco discharges into San Francisco Bay and had to bring its sewer system into compliance with a regional water board requirement, according to then-City Manager Mike Futrell. Public Works Director Eunejune Kim put the scale of the underlying problem in concrete terms when the ordinance passed: an estimated 35% of homes in the city still have Orangeburg sewer laterals, a paper-and-tar pipe material that was common in mid-century construction and is well past any reasonable service life today.
That detail changes what "35%" means for a seller. It is not a citywide risk spread evenly across every home. It is concentrated in exactly the housing stock that gives South San Francisco its character: the postwar single-family homes built in the boom years of the 1950s and 1960s. Councilmember Mark Addiego made the same point at the time, noting that pipe expected to last 50 years is now decades past that mark, and estimating that a full lateral replacement can run upward of $15,000. If your home falls into that construction era, and a large share of South San Francisco's does, the odds of a clean pass are not in your favor.
The Escrow Mechanic Nobody Budgets For
Here is where the timeline problem becomes real. If a lateral fails inspection and the repair cannot be finished before the scheduled transfer of title, the ordinance allows a time extension of up to 180 days, but only if the seller, agent, or buyer posts a $10,500 deposit into an escrow account with the city. That money is not a fee. It is released back once the lateral passes and a certificate of compliance is issued, but it has to be there first, sitting in escrow, while a licensed contractor schedules the repair and the city schedules its review.
Multi-unit residential buildings that share a single lateral are exempt, and homes served by the Westborough Water District fall outside the ordinance entirely. Once a home does pass, though, the certificate is good for a long time: 25 years, according to the city's own fact sheet, which is long enough that most sellers only encounter this process once or twice in a lifetime of homeownership. That rarity is exactly why it catches people off guard. Nobody remembers a rule they only deal with once.
What This Means in a Market That Moves in Weeks
Put the two facts next to each other. A home in South San Francisco can go from listing to accepted offer in 23 days on average, in a market tight enough that buyers are competing hard for what little is available. But the sewer lateral inspection does not move at market speed. It moves at contractor-scheduling speed and city-review speed, and if the pipe fails, it moves at repair-timeline speed, with a five-figure escrow deposit standing between the seller and a clean close if that repair cannot finish in time.
This is the piece that a hot market can hide until it can't. A seller who lists without ordering the CCTV inspection first is betting that a fast offer will also mean a fast close. In a city where a third of the housing stock likely has pipe material the ordinance was written specifically to catch, that is not a safe bet to make blind. The sellers who come out ahead in a market like this one are not just the ones who price and stage well. They are the ones who know which parts of the process cannot be rushed and get to them early, so the pipe inspection is already done by the time an offer arrives instead of becoming the thing that stalls it.
Frequently Asked Questions
Does the sewer lateral certificate transfer with the house, or does every sale need a new one? A passing certificate is valid for 25 years from the date it is issued. If a previous owner had the lateral inspected or replaced within that window, the current certificate may still be valid, which is worth checking before assuming a new inspection is required.
Are condos or townhomes subject to this ordinance? Multi-unit residential buildings that share a single sewer lateral are exempt from the point-of-sale requirement. Single-family homes and properties within a homeowners association are not exempt unless they meet one of the ordinance's specific carve-outs.
What happens if the lateral fails and I can't finish repairs before closing? The ordinance allows a 180-day extension, but it requires a $10,500 deposit posted into escrow with the city. The funds are returned once the lateral passes inspection and a compliance certificate is issued, but the deposit has to be in place before the extension is granted.
How would I know if my home has an Orangeburg lateral before I even list? The only reliable way is the CCTV inspection itself. Given that homes built in the 1950s and 1960s are the ones most likely affected, ordering the inspection early, before a buyer's inspection period puts it on someone else's timeline, gives a seller room to plan around whatever the video shows.
Sewer laterals are exactly the kind of pre-listing detail that gets missed when a seller is focused on staging and pricing, and exactly the kind of detail that can turn a fast, competitive sale into a delayed one. Watson Marshall Group manages this level of transaction logistics as part of its concierge approach to South San Francisco listings, coordinating inspections and repairs well before a home goes to market. If you're weighing a sale in South San Francisco, Request a Home Valuation and we'll walk through what your specific property needs before you list, not after you're already under contract.