Blog · October 14, 2026 · California
Half Moon Bay Flood Zone Map: checking a property's flood zone
Flood zones are set by FEMA, and checking one near San Carlos takes a few minutes.
Main page: San Mateo County, CA GIS & Parcel Viewer (official map link, county facts and neighboring maps).
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Weighing a property around Burlingame? A quick look at the Half Moon Bay flood zone map shows whether FEMA puts it in a high-risk zone, and no account is needed. In this Half Moon Bay guide: locating a parcel on FEMA's map, reading the zone codes, and confirming the outline on the county map.
Checking the Half Moon Bay flood zone map step by step
Flood zones come from FEMA's Flood Map Service Center: type an address near Belmont, then open the map view for that panel. Rural land near San Mateo with no street number can still be found: pan from the closest town then click the parcel area.
Getting to the right map
Begin with the San Mateo County parcel viewer; it covers each assessed parcel from Belmont to San Mateo. With a lot near San Mateo, type a street address, an owner's name or a parcel number, and the viewer zooms to the match. For land near Burlingame, a pop-up or side panel typically gives the owner of record, acreage on the tax roll, a parcel ID and in many cases the last transfer.
Deeds, plats and who keeps them
The map is an index, not the title: recorded deeds, plats and easements for land near Belmont are filed with the County Recorder. Long-held tracts near Burlingame may go back through a long string of deeds, so a title company is worth hiring on a real sale.
Where Half Moon Bay fits in
Half Moon Bay is part of San Mateo County, California, which means parcel data comes from the county. If you're looking near Millbrae, City or town hall handles matters such as zoning, permits and utilities inside its limits, while the county keeps the tax map. Land beyond the city limits toward San Carlos generally answers to county rules, not municipal ones.
A short flood checklist
Ask the seller whether the home has flooded for the house near Burlingame; an insurance quote early avoids surprises.
Zones on the Half Moon Bay flood zone map
For a parcel near San Mateo, zones beginning with A or V mark the Special Flood Hazard Area, meaning a 1% or greater chance of flooding each year. For a tract near Belmont, a shaded X area is moderate risk, roughly the 100- to 500-year range; unshaded X is minimal risk.
Beyond the mapped zones
Small streams around Burlingame may not have detailed mapping, so walk the land after rain. Marshy spots near Hillsborough can limit building too; the National Wetlands Inventory mapper shows mapped wetlands.
Parcel lines plus flood zones
FEMA's map shows zones but not ownership, so pair it with the San Mateo County parcel viewer for the outline of the tract near Hillsborough.
Next door to San Mateo County
San Mateo County touches Alameda County, San Francisco County, Santa Clara County, and Santa Cruz County; every one of them runs a separate parcel map. Acreage along the edge near Hillsborough may be split in two county records, so open the adjacent map as well. If you're looking near Hillsborough, the Platbookmapper state page lists each bordering county map for California.
A quick look at the area
Redwood City serves as the county seat, home to the main records offices. Other places on the map include Hillsborough, Belmont, Millbrae, and Burlingame, where town lots give way to larger tracts. About 726,353 people call San Mateo County home (Census Bureau estimate, 2023) across some 449 square miles. Places such as Don Edwards San Francisco Bay National Wildlife Refuge make handy reference points on the map near Belmont.
Getting answers from the right desk
Anything recorded against property around Hillsborough come from the County Recorder, usually searchable by name or document number. Zoning, permits and septic questions near Belmont go to planning, building or health offices, depending on whether the land is inside town limits.
What a flood zone means for a buyer
Closer to San Mateo, get the Elevation Certificate if one exists: it records the building's elevation against the base flood. Building or adding on near Hillsborough in a mapped zone can trigger elevation rules; check with the county or town building office before you plan.
Half Moon Bay: common questions
What does an AE label mean for a lot near Burlingame?
It depends, but both are high-risk zones, but only AE has a base flood elevation, so builders near San Carlos design to that elevation.
How often are flood maps updated around Hillsborough?
Short answer: zones near Hillsborough can shift when FEMA updates a panel; your community is notified before changes take effect.
Do I need to worry about flooding in Zone X in Half Moon Bay?
It depends, but X zones around Millbrae are lower risk, not no risk; FEMA notes that a large share of claims come from these areas.
Does the county parcel map show flood zones in Half Moon Bay?
A flood layer may appear in the San Mateo County parcel viewer layer list, but FEMA's own map is the official source.
How is land described in California deeds near San Mateo?
For property near San Carlos, deeds use lot and block, metes and bounds or survey descriptions, and the parcel record often summarizes it.
Open the official San Mateo County, CA parcel map See it in the Platbookmapper directory
Not a survey. County GIS and tax parcel maps are assessment and planning layers. They are not a substitute for a recorded plat, deed, or licensed survey, especially for fences, setbacks, or boundary disputes.