Foster City — An Engineered Island, a $90 Million Levee Fix, and Its Own City Hall Since 1971

What Actually Makes Foster City Different

Most waterfront communities on this site grew up around water that was already there. Foster City is the opposite kind of place: it is a single, roughly 2,600-acre island in San Francisco Bay that was deliberately re-engineered, from a working cattle-and-hay ranch into a planned residential city, by one developer working largely from a blank slate. The land itself has an older story worth knowing first -- USGS maps show it as undeveloped marsh as early as 1892, and a rancher named Frank Brewer built a levee around it in 1900 specifically to create dry pasture for grazing cattle and cultivating hay, which is why the land carried the name Brewer Island for more than half a century before anyone thought to build a city on it. In 1958, T. Jack Foster, a developer from an Oklahoma real-estate family, and Bay Area developer Richard Grant secured a $200,000 option on the island; Foster bought out Grant's interest by 1960 and, by 1962, had already put $4.7 million of his own money into re-grading the land -- two full years before the first home would be built. Crews deposited roughly 18 million cubic yards of compacted fill around and atop the original marsh, raising the island's surface by about 6 feet, and excavated an artificial lagoon through its center that would become both the development's signature amenity and, functionally, its stormwater system. The first 200 families moved in at the end of 1964; by 1966 the population had reached 5,000; and on April 27, 1971, Foster City incorporated as its own independent municipality, with its own elected mayor and city council rather than remaining an unincorporated development under county governance.

That last fact is the genuine, documented line between Foster City and its immediate neighbor to the south, Redwood Shores -- a comparison this page draws carefully rather than treating the two as interchangeable, because they are not. Leslie Salt Company's real-estate arm proposed a Redwood Shores community modeled explicitly on Foster City's example starting around 1959, but development there moved on a different track and a different timeline: the company ran out of money to continue building in 1972, Mobil Oil Estates bought the unfinished project in 1973, and the community's build-out didn't gain real momentum again until the 1982 economic recovery, when its office campuses (the eventual home of Oracle Corporation's headquarters, among others) began to fill in. More fundamentally, Redwood Shores never incorporated as its own city at all -- it remains an unincorporated-in-character neighborhood annexed for municipal services to Redwood City, a city it is not even physically connected to by road without first passing through San Carlos. Foster City, by contrast, has run its own city government, set its own municipal tax rate, and made its own infrastructure decisions -- including the levee bond described below -- continuously since 1971. A buyer comparing the two is comparing a fully self-governing city that was largely finished as a residential build-out by the late 1960s against a still-part-of-a-larger-city district whose corporate-campus core filled in a decade or more later.

Foster City's defining water feature, the lagoon system, is also a more managed and more extensive piece of infrastructure than a casual drive-by suggests. City materials describe more than 200 surface acres of lagoon winding roughly five miles through the city's neighborhoods, with some sources citing as much as 16 miles of connected waterway frontage across the full system -- a real disagreement in how the figure gets measured that this page states rather than resolves. The lagoon is entirely enclosed by floodgates, with automated intake gates and a pump station drawing San Francisco Bay water in to keep it circulating and clean, and the capacity to pump water back out to the Bay at up to 250,000 gallons per minute if needed for flood control; water levels are deliberately raised on weekends and holidays and lowered midweek to maximize exchange. Because it's gated and enclosed, the lagoon has none of the natural tidal current or wave action of an open Bay inlet -- a meaningfully calmer, more controlled everyday water experience, and part of why the city has banned gasoline and diesel-powered boats entirely: only sailboats, paddleboards, kayaks, windsurfers, and electric-powered craft are allowed, under a citywide 5 mph speed limit. Twenty-four city parks cover more than 200 acres along that shoreline, including sandy swimming beaches at Erckenbrack and Marlin parks and the 20.75-acre Leo J. Ryan Memorial Park -- renamed in 1979, a year after Congressman Leo J. Ryan, who represented this district in Congress from 1973 until his 1978 assassination in Guyana during the Jonestown investigation, becoming the only sitting member of Congress ever killed in the line of duty.

The 2014-to-2024 levee story is the single most consequential, specifically local hazard fact a buyer should understand here, and it is a genuinely different kind of hazard story than the wildfire, hurricane, or fault-line narratives that dominate other markets on this site. FEMA determined in 2014 that Foster City's ring levee -- the engineered barrier separating the entire built-up island from San Francisco Bay -- no longer met the federal standard for 1%-annual-chance flood protection, which would have remapped much of the city into a Special Flood Hazard Area and made flood insurance mandatory for anyone with a federally backed mortgage. Rather than accept that outcome, Foster City voters approved Measure P in June 2018: a $90 million general obligation bond, costing roughly $40 per $100,000 of assessed property value annually (about $560 a year on an average-priced home at the time) for 30 years, explicitly pitched against an estimated $2,000 to $3,000-plus a year in mandatory flood insurance premiums indefinitely if the city did nothing. Construction raised the levee by as much as 8 feet in places, ran from October 2020 through completion in early 2024, and FEMA has since restored the levee's accreditation -- land within Foster City is classified in flood Zone X, the lowest federal flood-risk category, meaning the flood insurance mandate does not currently apply. That is a real, resolved, and expensive civic achievement, not a footnote, and it is the honest center of this page's hazard coverage rather than a generic Bay Area liquefaction paragraph borrowed from elsewhere.

Several things this research could not pin to a single confirmed figure and does not invent: a clean, Foster City-specific waterfront-versus-inland or lagoon-frontage price premium expressed as a percentage; one reconciled median home price (Zillow's roughly $1.86 million citywide average value, Redfin's roughly $1.6 million trailing 3-month median, and a June 2026 sold-homes snapshot citing a $1.43 million median all disagree by hundreds of thousands of dollars, and this page states the range rather than picking a winner); a confirmed current sunset date or exact remaining term for the Measure P special tax; and a Foster City-specific current homeowners or flood insurance premium as opposed to general California or San Mateo County ranges. Anyone evaluating a purchase or move here should confirm current numbers directly with the San Mateo County Assessor, the City of Foster City's Finance and Public Works Departments, a California-licensed insurance agent, and a local buyer's agent rather than assuming a figure found online is current.