The Two Airport Noise Maps Every San Bruno Remodel Has to Clear

A homeowner in San Bruno decides to finally open up the kitchen and add a primary suite. The contractor pulls comps, the budget lands at a number that feels reasonable for the neighborhood, and the permit application goes in. Nobody flags the airport. Then partway through plan check, the city comes back with a requirement nobody budgeted for: FAA-standard sound insulation, because the project crossed a threshold tied to the home's value, not its square footage.

This isn't a rare edge case. It's baked into how San Bruno regulates construction near SFO, and it catches people because the rule that governs your remodel and the rule that governs your disclosure paperwork are not the same rule, built from the same map, on the same timeline.

Two Systems, Two Maps, One House

San Bruno homeowners deal with airport noise in two completely separate regulatory tracks. One is a state-mandated disclosure requirement that every seller in San Mateo County has to complete, built around a noise contour map from 1983. The other is a local building code trigger, tied to a 2020 noise forecast, that decides whether your renovation has to include federally specified sound insulation. A property can clear one and still trip the other. Understanding which map governs which moment in a transaction is the difference between a smooth listing and a permit delay nobody saw coming.

What the 1983 Map Still Controls

Every property transfer in San Mateo County falls under a disclosure requirement that predates most current homeowners. State law requires sellers to reveal noise and other nuisance factors in a Real Estate Transfer Disclosure Statement, and California's Business and Professions Code Section 11010 requires that anyone offering property within an airport influence area disclose the presence of nearby airports before the sale closes, a rule that applies to every parcel in the county under what the C/CAG Airport Land Use Commission calls Area A. San Bruno layers its own local version on top of that state baseline: under Chapter 6.18 of the municipal code, any seller of a single or multi-family home in the city, or the agent representing that seller, must make specific airport noise disclosures on a Local Option Real Estate Transfer Disclosure Statement before title transfers, not just the general state notice.

The actual mechanics of that disclosure are more specific to San Bruno than most sellers expect. A sample transfer disclosure statement published by the National Academies Press shows San Bruno properties, at their closest point, sitting about a quarter mile from SFO's developed perimeter, and at their farthest point, roughly four miles away, according to the same source. That's not a small range. A home a quarter mile from the runway and a home four miles away are both technically "in the vicinity of an airport" for disclosure purposes, but they are not living the same noise reality, and the paperwork treats them almost identically.

The disclosure form itself has to attach a specific document: the 1983 65 CNEL Noise Contour map, referenced by ordinance in San Bruno, Pacifica, and South San Francisco alike. Sellers are also directed to flyquietsfo.com, the airport's own tool for locating a property against that contour, as the primary way to confirm where a given address falls.

That map is more than four decades old. It is still the legal reference point for the disclosure form, regardless of how flight patterns or aircraft noise levels have shifted since.

What the 2020 Forecast Actually Triggers

The building code operates on a newer, tighter timeline. San Bruno's municipal code sets a rule that has nothing to do with disclosure and everything to do with permits: any residential structure sitting within the 65 CNEL contour, as determined by the 2020 Noise Forecast adopted under the SFO Comprehensive Airport Land Use Compatibility Plan, must meet FAA noise insulation standards if it's newly constructed, or if it's renovated at a cost equal to or greater than 25 percent of the property's valuation, under Chapter 11.04 of the San Bruno Municipal Code. The city adopted the current version of this rule through Ordinance 1968 in November 2025, so it's the operative standard right now, not a legacy holdover.

This isn't a brand-new concept. The same 25-percent-of-value threshold shows up in historical disclosure language going back to a state rule effective January 1, 1993, which required that any property reconstructed or renovated at 25 percent or more of current market value be insulated to FAA standards, per the same National Academies sample statement referenced above. The rule has persisted for over three decades. What's changed is the map behind it, from a 1983 contour to a 2020 forecast, which can shift which specific homes fall inside the boundary even while the percentage threshold stays fixed.

Here's the practical version of what that means for a project: a kitchen refresh or bathroom remodel is unlikely to hit 25 percent of a home's value on its own. A significant addition, a full interior gut, or a rebuild after damage is a different story, and those are exactly the projects where a seller or buyer might be mid-permit before anyone checks which side of the 65 CNEL line the address falls on.

The Retrofit Is Free, But Not Without a Trade

There's a piece of this most sellers never hear about until someone tells them directly: SFO runs a program that will pay for the exact insulation upgrade the building code might otherwise require you to fund yourself.

The airport's Noise Insulation Program includes an Expanded Eligibility Initiative, and one recent phase of that program treated up to 47 residential properties across Millbrae, San Bruno, and South San Francisco, with work scoped to include window and door replacement, HVAC installation and associated electrical work, insulation, sheetrock, and finish carpentry and painting, according to SFO's own procurement documentation for the project. The project manager of record on that documentation is Luis Moreno, reachable through SFO's Noise Insulation Program office. New phases open periodically, so the right move for an eligible homeowner is confirming current status directly rather than assuming a past cycle is still taking applications.

That's a real, no-cost path to compliance for an eligible home. But it comes with a permanent condition: participation requires granting the airport an avigation easement. An avigation easement is a recorded property right that gives aircraft the legal right to use the airspace above your home and precludes you from taking legal action over the noise, vibration, or fumes that come with it. Once recorded, it stays with the title in perpetuity and transfers to whoever buys the home next, unless the municipality removes it. There's also a restriction that outlives the renovation itself: if a property has already received insulation under the FAA program, the owner cannot deliberately act to reduce or destroy the effectiveness of that noise mitigation, per the same historical disclosure language referenced earlier.

That's the actual decision a seller or a homeowner planning a renovation is making. Fund the insulation privately and keep full rights over what happens above the property, or take the free retrofit and permanently sign over a piece of that airspace along with the legal standing to complain about what flies through it.

Before You Pull a Permit or List the House

1. Confirm your address against the current 65 CNEL contour using flyquietsfo.com rather than assuming your neighborhood's general reputation tells you where you fall.
2. If you're planning any renovation, get a rough valuation of the home before finalizing scope, so you know whether the project is approaching that 25 percent threshold before you're mid-permit.
3. Ask the city's Aircraft Noise Insulation office whether your address currently qualifies for the SFO Expanded Eligibility Initiative before assuming you'll need to fund insulation out of pocket.
4. If an avigation easement is on the table, read the actual language rather than the summary. It's a permanent transfer of a property right, not a formality.
5. If you're selling, confirm which disclosure documents are attached to your transfer statement, including the required contour map, well before you're under contract.

FAQ

Does a small remodel ever trigger the FAA insulation requirement?

Usually not on its own. The threshold is tied to 25 percent of the property's valuation, so a single kitchen or bathroom update is unlikely to reach it. Larger additions, full interior renovations, and rebuilds after damage are where the calculation starts to matter.

If my home already has FAA-grade insulated windows, can I replace them with something else later?

Not without consequence. Under the standard that's been in place since the early 1990s, an owner whose property already received noise insulation under the FAA program is barred from deliberately acting to reduce or destroy the effectiveness of that mitigation.

Does the free retrofit program cost anything down the line?

Not in dollars, but the avigation easement it requires is permanent and recorded on title. It transfers with the home to future owners and limits legal claims tied to aircraft noise indefinitely, which is worth weighing against the value of the upgrade itself.

If you're weighing a renovation against a listing timeline anywhere in San Bruno, this is exactly the kind of paperwork mismatch that's easy to miss and expensive to catch late. Andrew Klink has walked Peninsula sellers through these overlapping rules enough times to know where they usually surface. Schedule a complimentary Peninsula market consultation before you finalize scope or list the house, and we'll map out what actually applies to your address.