Two neighbors on the same lagoon block in Foster City can own nearly identical homes and pay noticeably different amounts for the same flood protection. Not because of square footage. Not because of a renovated kitchen or a better dock. Because of the year on their grant deed.
That gap is not a rumor or a rounding error. It is written into how California funds public infrastructure, and it shows up on the property tax bill every single year, long after the news coverage of the vote that created it has faded.
The $90 Million Line Nobody Reads Before Making an Offer
In June 2018, Foster City voters approved Measure P, a $90 million general obligation bond to rebuild the city's aging bay-front levee. FEMA had told the city in 2014 that the existing levee did not meet minimum flood protection standards, which put roughly 9,000 Foster City properties at risk of being pulled into a mandatory flood insurance zone. Voters said yes by a wide margin, the city issued $85 million of the authorized bonds on August 5, 2020, and construction ran for roughly three and a half years before wrapping up in February 2024. Shimmick Construction built it. Schaaf & Wheeler Consulting Civil Engineers designed it.
None of that is controversial or hidden. What surprises buyers is what comes next: the bond does not stop costing money when the construction crews leave. The Measure P levy started appearing on Foster City tax bills in fall 2020 and, per the city's own project documents, continues for 30 years, meaning it runs through roughly 2050. The rate is set annually and has run in the range of $33 to $40 per $100,000 of assessed property value depending on the year.
That per-$100,000 phrase is where the real story lives.
Same Levee, Different Bill
California assesses residential property under Proposition 13, which caps annual increases in assessed value at 2 percent unless the property changes hands. A home that last sold years ago carries an assessed value that has crept up slowly and predictably. A home that just closed escrow gets reassessed at whatever the buyer paid.
Because Measure P is billed as a rate per $100,000 of assessed value, not a flat fee per household, two owners protected by the exact same stretch of rebuilt levee can owe very different amounts.
| Owner | Assessed value | Approximate annual Measure P tax (at $40 per $100,000) |
|---|---|---|
| Longtime owner, protected by years of Prop 13's 2 percent annual cap | $500,000 | about $200 |
| Recent buyer, reassessed at a purchase price roughly three times higher | $1,500,000 | about $600 |
Same neighborhood. Same levee. A three-to-one difference in what each household pays for it, purely because of timing. A former Foster City mayor put it plainly when the bond was still fresh, warning residents that "there will be periodic assessments as it moves along," a line that reads less like a warning about cost and more like a description of exactly how the mechanics work.
This is not unique to Measure P. It is how every Mello-Roos district and general obligation bond levy in California behaves, because the tax rides on assessed value rather than market value or household income. But Foster City is one of the few Peninsula cities where the underlying reason for the levy, keeping an entire bayfront community out of a federal flood zone, is specific enough that buyers should actually understand the trade before they write an offer, not just accept the line item as background noise on a closing disclosure.
The Other Half of the Trade
Here is the part that gets lost when a buyer only sees the tax bill and not the reason for it. Without the completed levee, Foster City risked FEMA reclassifying the city into a mapped flood hazard zone. That reclassification would have forced homeowners with federally backed mortgages to carry flood insurance, priced at an estimated $2,000 to $3,000 or more per year, indefinitely, according to city officials at the time the bond was proposed.
Instead, the city paid to raise and reinforce the levee, and today Foster City remains in FEMA Zone X, the designation under which flood insurance is not federally required. A homeowner paying $200 to $600 a year in Measure P tax is trading that for insurance costs that would otherwise run four to fifteen times higher, every year, with no 30-year end date.
This is also where a buyer relying only on portal data can get confused. Consumer real estate sites run their own hazard models on top of the official FEMA designation, and those models can flag a high share of Foster City properties as facing severe flood risk over a 30-year horizon. That modeled long-range risk score and the current FEMA Zone X designation are two different things measuring two different questions. One is a climate projection. The other is today's actual regulatory flood zone, the one that determines whether your lender requires insurance right now. Both are true. Neither cancels the other out. A buyer who only sees the alarming hazard score without understanding what the completed levee actually accomplished is working from half the picture.
If You're Cross-Shopping Against San Carlos or Redwood Shores
Buyers comparing Foster City to San Carlos or Redwood Shores on price per square foot alone are missing a variable that does not show up in that comparison. San Carlos was never part of this conversation because it isn't a bayfront community built on reclaimed fill, so there's no equivalent levee bond in play. Redwood Shores is a different story worth flagging: it was built on reclaimed bay fill in the same era as Foster City and relies on its own levee system for the same basic reason.
A UC Berkeley engineering professor who has studied Bay Area sea level rise noted, when Measure P passed, that Foster City was likely to be the first of several bayfront communities to face this exact decision, naming Redwood Shores specifically as a community that could eventually confront the same choice. That does not mean Redwood Shores currently carries an equivalent bond levy. It means a buyer evaluating any lagoon-front or reclaimed-land property on the Peninsula, not just in Foster City, should ask the same question: is there a special assessment tied to flood or levee infrastructure on this specific parcel, and how many years are left on it?
Where to Actually Find This Before You Write an Offer
This is not information a listing photo or a Zestimate surfaces. It lives in three places: the preliminary title report your escrow company pulls once you're in contract, the seller's mandatory disclosure package, and the actual county property tax bill, which itemizes special assessments separately from the base 1 percent rate. A buyer's agent who knows to ask for the current Measure P rate and the years remaining on the levy, before an offer goes in rather than after it's accepted, can build that number into the real monthly cost of ownership instead of discovering it on the first tax bill.
Does the Measure P tax show up when I search listings online? No. It is a line item on the county property tax bill, not a field most consumer real estate sites display. You have to look at the actual bill, the preliminary title report, or the seller disclosures to see it.
How much longer does the tax run? The levy began appearing on tax bills in fall 2020 and is structured to continue for 30 years, putting the end date at roughly 2050.
Does the completed levee mean flood insurance is required or not? Not required. Foster City's completed levee keeps the city in FEMA Zone X, the designation under which flood insurance is not federally mandated, even though some portal hazard models still flag long-range flood risk separately.
Numbers like this are exactly why a buyer or seller on the Peninsula benefits from someone who reads the tax bill line by line instead of just the sale price. If you are weighing a Foster City purchase against a comparable home in San Carlos, Redwood City, or Redwood Shores and want the real annual cost laid out before you write an offer, Robert Pedro has spent three decades running these numbers for Peninsula buyers and can walk you through what a specific property actually costs to own, not just what it costs to close on.
