Does Hillsdale flood?
Hillsdale, San Mateo, CA · ZIP code 94403: the ZIP code on 21 of the 21 flood insurance claims counted here. ZIP codes do not follow neighborhood lines.
Yes. Insured properties in and around Hillsdale have filed flood claims. About 3.3% of Hillsdale’s mapped area is inside FEMA’s Special Flood Hazard Area; the rest is in moderate or minimal-hazard Zone X. NFIP flood insurance records list 21 claims from the Census block groups that cover Hillsdale, from 1978 through 2023. 16 of them received a payment, totaling $213,237 (not adjusted for inflation). The busiest years were 2022 (5 claims), 1983 (3 claims), 1986 (2 claims).
What this page counts as Hillsdale
We could not find an openly licensed official boundary for Hillsdale, so this page uses a census-based area. For this page, Hillsdale means the 2010 Census block groups whose center lies within 1.6 km (1.0 miles) of the U.S. Geological Survey (GNIS) map point for Hillsdale (feature 1658755) and inside the San Mateo city limits (U.S. Census Bureau), each block group going to the nearest of the places we cover. Every number below is for exactly those block groups (listed in “How these numbers were made”), so the edges are approximate and may include or leave out a few blocks people would call Hillsdale. Sources: U.S. Census Bureau TIGERweb, 2010 Census Block Groups and U.S. Geological Survey, Geographic Names Information System (GNIS) domestic names.
Past claims do not predict future flooding, and a neighborhood figure cannot tell you about one building. Look up the exact address on the FEMA Flood Map Service Center and get flood insurance quotes before you sign a lease or a contract.
Check a specific address in Hillsdale
Neighborhood figures are averages. Our address check looks up the FEMA flood zone and California’s fire hazard severity zone at one address, from the same public maps: check if your address is in a flood zone.
Flood zones street by street in Hillsdale
The named streets in Hillsdale, longest first, with how much of each street’s length inside Hillsdale lies in FEMA’s high-risk flood zones (the Special Flood Hazard Area, zones A and V). Length is the part inside Hillsdale; the main zone is the FEMA zone covering most of that length. A street can cross several zones, so the zone at one address can differ from the street’s main zone: check the address above for that. 85 shorter streets are not listed.
| Street | Length | In high-risk zones | Main zone |
|---|---|---|---|
| El Camino Real | 2.0 mi | 8.4% | X (unshaded, minimal) (92%) |
| S El Camino Real | 1.8 mi | 9.8% | X (unshaded, minimal) (90%) |
| J Arthur Younger Fwy | 1.6 mi | 0.0% | X (unshaded, minimal) (100%) |
| Pacific Blvd | 1.2 mi | 7.8% | X (unshaded, minimal) (92%) |
| S Delaware St | 1.1 mi | 0.0% | X (unshaded, minimal) (100%) |
| Edison St | 1.0 mi | 0.0% | X (unshaded, minimal) (87%) |
| Hacienda St | 5,200 ft | 0.0% | X (unshaded, minimal) (94%) |
| Saratoga Dr | 4,540 ft | 5.6% | X (unshaded, minimal) (94%) |
| Bermuda Dr | 3,990 ft | 0.0% | X (unshaded, minimal) (100%) |
| 19th Ave | 3,870 ft | 0.0% | X (unshaded, minimal) (97%) |
| W Hillsdale Blvd | 3,750 ft | 1.0% | X (shaded, 0.2% annual chance) (99%) |
| E Hillsdale Blvd | 3,500 ft | 86% | AO (81%) |
| Isabelle Ave | 3,440 ft | 0.0% | X (unshaded, minimal) (100%) |
| 31st Ave | 3,370 ft | 0.0% | X (unshaded, minimal) (100%) |
| Flores St | 3,330 ft | 0.0% | X (unshaded, minimal) (100%) |
| W 25th Ave | 3,150 ft | 0.0% | X (unshaded, minimal) (100%) |
| 28th Ave | 3,050 ft | 0.0% | X (unshaded, minimal) (100%) |
| 27th Ave | 2,980 ft | 0.0% | X (unshaded, minimal) (100%) |
| Curtiss St | 2,940 ft | 12% | X (unshaded, minimal) (88%) |
| Palm Ave | 2,840 ft | 37% | X (unshaded, minimal) (49%) |
| Franklin Pkwy W | 2,720 ft | 0.0% | X (unshaded, minimal) (100%) |
| 37th Ave | 2,670 ft | 0.0% | X (unshaded, minimal) (100%) |
| 24th Ave | 2,640 ft | 0.0% | X (unshaded, minimal) (100%) |
| 29th Ave | 2,630 ft | 0.0% | X (unshaded, minimal) (100%) |
| 36th Ave | 2,410 ft | 0.0% | X (unshaded, minimal) (100%) |
Streets: U.S. Census Bureau TIGERweb, Transportation (primary, secondary and local roads). Flood zones: FEMA National Flood Hazard Layer (NFHL), Flood Hazard Zones and FIRM Panels, retrieved November 4, 2026. Each street is clipped to the area boundary and measured in an equal-area projection. Street lengths are rounded.
Flood zones in Hillsdale
Share of Hillsdale’s mapped area (about 4.615 km²) in each FEMA flood zone, from FEMA National Flood Hazard Layer (NFHL), Flood Hazard Zones and FIRM Panels. Mapped base flood elevations inside the neighborhood range from 12 to 23 feet. Effective date of the FIRM panel(s) covering it (06081C0162F, 06081C0166F, 06081C0168F): July 16, 2015.
| FEMA zone | Share of area |
|---|---|
| X (unshaded, minimal) | 93% |
| X (shaded, 0.2% annual chance) | 4.0% |
| AO | 2.0% |
| AH | 1.2% |
| AE | 0.1% |
What the zones mean
- Zone AE (and A, AH, AO)
- High-risk: part of the Special Flood Hazard Area (SFHA), the area FEMA maps as having a 1-percent chance of flooding in any given year (the “100-year” or base flood). AE areas have a mapped base flood elevation.
- Zone VE (and V)
- High-risk coastal areas, also in the SFHA, where the base flood is expected to bring additional hazards from storm waves.
- Zone X (shaded)
- Moderate hazard: between the limits of the 1-percent and the 0.2-percent-annual-chance (“500-year”) flood.
- Zone X (unshaded)
- Minimal hazard: outside the SFHA and higher than the 0.2-percent-annual-chance flood elevation. Minimal is not zero: flood claims are filed from X zones too.
Source: FEMA Glossary: Flood Zones.
Flood insurance claims over time
Claims filed under the National Flood Insurance Program (NFIP) from the 2010 Census block groups that cover Hillsdale. This area is made of whole block groups, so every claim counted here comes from inside it. Only insured properties appear, so these counts understate total flooding.
By decade
| Decade | Claims | Paid |
|---|---|---|
| 1970s | 1 | $924 |
| 1980s | 8 | $83,927 |
| 1990s | 2 | $22,199 |
| 2000s | 3 | $850 |
| 2020s | 7 | $105,337 |
By year of loss
Named flood events with the most claims
- Flooding: 8 claims
- California Atmospheric River: 6 claims
- Pineapple Express - Southern: 1 claims
FEMA labels some events only as “Flooding”. Claims by the flood zone the property was rated in:
- A/AE/AH/AO (high risk): 13
- X/B/C (moderate or minimal): 8
How much is flood insurance in Hillsdale?
The typical National Flood Insurance Program policy on single-family homes in Hillsdale costs $1,547 a year: the median of 66 policies that started between September 1, 2025 and August 31, 2026. Half of them cost between $1,262 and $1,868. That is the full amount paid for the year, the premium plus FEMA’s fees and surcharges, and every one of these policies is priced under Risk Rating 2.0. A quote for one building can be far from this: its elevation, foundation, age, coverage and deductible all change the price. Private flood insurance is not included.
Source: FEMA OpenFEMA Dataset: FIMA NFIP Redacted Policies - v3, computed November 4, 2026.
Why home insurance costs what it does in Hillsdale
This section is educational and is not insurance advice.
Flood insurance
ZIP codes do not follow neighborhood lines. This is a ZIP code on at least 5% of the flood claims counted for Hillsdale, within 10 km of it.
- ZIP code 94403: the median National Flood Insurance Program policy cost for single-family homes was $1,265 a year, the middle of 166 policies that started between September 1, 2025 and August 31, 2026. Half of them cost between $1,090 and $1,643. These policies are priced under Risk Rating 2.0.
- ZIP code 94403: NFIP records list 43 flood claims with a loss year from 1978 through 2023. The claims dataset is as of September 8, 2026.
Fire and wind
- Official state fire hazard maps: Very High 0%, High 0%, Moderate 0%, outside any mapped zone 100% of Hillsdale. The publisher of these maps does not endorse this site.
- USDA Forest Service Wildfire Risk to Communities gives San Mateo, CA a Risk to Homes national percentile rank of 0.511, which its methods call Medium (above the 40th percentile and below the 70th). That is the city rating, not a rating of Hillsdale alone. The summary file is dated April 15, 2026.
What to ask your agent
- Ask the agent how old the roof is.
- Ask whether a wind-mitigation discount is available for this house.
- Ask how flood coverage differs from the homeowners policy. A standard homeowners policy does not cover flood. Flood coverage is a separate policy.
- Ask whether the policy has a separate hurricane or windstorm deductible, and how that deductible is calculated.
- Ask when coverage would start. A new National Flood Insurance Program policy generally takes effect 30 days after purchase.
Flood coverage and the 30-day wait: FEMA fact sheet, Jan. 21, 2025; 44 CFR 61.11.
What do NFIP records show for flood insurance in Hillsdale?
ZIP code 94403: the median National Flood Insurance Program policy cost for single-family homes was $1,265 a year, the middle of 166 policies that started between September 1, 2025 and August 31, 2026. Half of them cost between $1,090 and $1,643. These policies are priced under Risk Rating 2.0. ZIP code 94403: NFIP records list 43 flood claims with a loss year from 1978 through 2023. The claims dataset is as of September 8, 2026.
What do public fire and wind records show for Hillsdale?
Official state fire hazard maps: Very High 0%, High 0%, Moderate 0%, outside any mapped zone 100% of Hillsdale. The publisher of these maps does not endorse this site. USDA Forest Service Wildfire Risk to Communities gives San Mateo, CA a Risk to Homes national percentile rank of 0.511, which its methods call Medium (above the 40th percentile and below the 70th). That is the city rating, not a rating of Hillsdale alone. The summary file is dated April 15, 2026.
What should I ask an insurance agent about a home in Hillsdale?
Ask the agent how old the roof is. Ask whether a wind-mitigation discount is available for this house. Ask how flood coverage differs from the homeowners policy. A standard homeowners policy does not cover flood. Flood coverage is a separate policy. Ask whether the policy has a separate hurricane or windstorm deductible, and how that deductible is calculated. Ask when coverage would start. A new National Flood Insurance Program policy generally takes effect 30 days after purchase.
Sources: OpenFEMA NFIP Redacted Policies v3; OpenFEMA NFIP Redacted Claims v3; Fire Hazard Severity Zones; USDA Forest Service, Wildfire Risk to Communities, community summaries; Wildfire Risk to Communities methods.
Insurance agency or real estate agent? Sponsor this page.
Extreme heat in Hillsdale
FEMA’s National Risk Index rates heat wave risk for the census tracts that cover Hillsdale as: “Relatively Low” for 100% of the area. Their heat wave risk scores range from 24 to 52 out of 100 (national percentiles). The index weighs how often heat waves happen, what they are expected to cost, and how vulnerable and resilient the community is, so a dense area can rate differently from a nearby one (FEMA National Risk Index, Census Tracts feature layer, Version 1.20.0 (December 2025)).
Trees shade streets and buildings and cool the air around them (U.S. EPA: Using Trees and Vegetation to Reduce Heat Islands). In the USDA Forest Service’s 2025 satellite-based tree canopy map, trees cover about 5.7% of Hillsdale’s area on average, compared with 5.7% for San Mateo as a whole (the 1 San Mateo areas on this site combined) (USDA Forest Service. 2026. USFS NLCD Percent Tree Canopy CONUS v2025-6 (2025 map). Salt Lake City, UT).
During a heat advisory, follow the National Weather Service: Heat Safety guidance. Neighborhood averages cannot tell you how hot a particular home, block or unit gets.
Fire hazard severity zones in Hillsdale
California’s 2025 Fire Hazard Severity Zone maps do not place any of Hillsdale in a moderate, high or very high zone (CAL FIRE Office of the State Fire Marshal, Fire Hazard Severity Zones). Wildfire smoke and wind-blown embers can still reach areas outside the zones.
Fire hazard data: CAL FIRE Office of the State Fire Marshal. CAL FIRE does not endorse this site.
This product uses the Federal Emergency Management Agency’s National Risk Index dataset API or downloadable datasets but is not endorsed by FEMA. The Federal Government or FEMA cannot vouch for the data or analyses derived from these data after the data have been retrieved from the Agency's website(s). FEMA: “The National Risk Index data are meant for planning purposes only. This National Risk Index dataset was created for broad nationwide comparisons and is not a substitute for localized risk assessment analysis.”
Before you rent or buy in Hillsdale
- Look up the exact address on the FEMA Flood Map Service Center; a neighborhood can mix high-risk and minimal-hazard zones.
- Ask the landlord or seller about past flooding and flood insurance claims at the property.
- Get a flood insurance quote early: new NFIP policies usually take 30 days to start (FloodSmart (NFIP): Buy a Flood Insurance Policy).
- Ask which floor the unit is on and where parking, storage and mechanical equipment sit.
Living in Hillsdale
Flood maps are only one part of choosing a neighborhood. To compare Hillsdale with other San Mateo neighborhoods on more than flooding, see San Mateo on StrollPlace.
Buyer and renter FAQ
Does Hillsdale flood?
Yes. Insured properties in and around Hillsdale have filed flood claims. About 3.3% of Hillsdale’s mapped area is inside FEMA’s Special Flood Hazard Area; the rest is in moderate or minimal-hazard Zone X. NFIP flood insurance records list 21 claims from the Census block groups that cover Hillsdale, from 1978 through 2023. 16 of them received a payment, totaling $213,237 (not adjusted for inflation). The busiest years were 2022 (5 claims), 1983 (3 claims), 1986 (2 claims). Past claims do not predict future flooding, and conditions vary street by street, so check the specific address.
Is Hillsdale in a flood zone?
About 3.3% of Hillsdale’s mapped area is inside FEMA’s Special Flood Hazard Area; the rest is in moderate or minimal-hazard Zone X. Shares by zone: X (unshaded, minimal) 93%; X (shaded, 0.2% annual chance) 4.0%; AO 2.0%; AH 1.2%; AE 0.1%. The FIRM panel(s) covering it took effect July 16, 2015.
Which streets in Hillsdale are in a high-risk flood zone?
Most of the length of E Hillsdale Blvd lies in FEMA high-risk zones (the Special Flood Hazard Area). Less than 10% of El Camino Real, S El Camino Real, J Arthur Younger Fwy, Pacific Blvd, S Delaware St, Edison St, Hacienda St and Saratoga Dr does. Zones can change along a street, so check the exact address.
What ZIP code is Hillsdale in?
Hillsdale is in San Mateo, CA. ZIP code 94403: the ZIP code on 21 of the 21 flood insurance claims counted here. ZIP codes do not follow neighborhood lines. Check the specific address for its own flood zone.
Do renters need flood insurance?
Standard renters policies usually do not cover flood. Renters in a community that participates in the NFIP can buy contents-only flood coverage, up to $100,000 for belongings.
How long does a new flood policy take to start?
A new NFIP policy generally takes effect 30 days after purchase. Exceptions include no wait when the policy is bought while making, increasing, extending or renewing a mortgage, and a one-day wait in a newly designated high-risk zone within 12 months of the map change.
How much coverage can NFIP provide?
For a one-to-four family home, NFIP building coverage goes up to $250,000 and contents coverage up to $100,000. You can buy flood insurance even if you are not in a high-risk zone, as long as your community participates in the NFIP.
How much is flood insurance in Hillsdale?
The typical NFIP flood insurance policy on single-family homes in Hillsdale cost $1,547 a year: the median of 66 policies that started between September 1, 2025 and August 31, 2026. Half cost between $1,262 and $1,868. One building’s quote can be far from this; its elevation, foundation, age, coverage and deductible all change the price.
FAQ sources: FloodSmart (NFIP): Buy a Flood Insurance Policy; FEMA Fact Sheet: Think you don’t need flood insurance? Think again (Jan. 21, 2025); 44 CFR 61.11, Effective date and time of coverage.
Nearby neighborhoods
How these numbers were made
Area: the census-based definition above, using U.S. Census Bureau TIGERweb, 2010 Census Block Groups and U.S. Geological Survey, Geographic Names Information System (GNIS) domestic names. Flood zone shares: the area polygon intersected with FEMA National Flood Hazard Layer (NFHL), Flood Hazard Zones and FIRM Panels, area computed in an equal-area projection; retrieved November 4, 2026. Claims: OpenFEMA NFIP Redacted Claims v3 records for San Mateo County (county code 06081), dataset as of September 8, 2026, retrieved November 4, 2026. Claims are counted for exactly the block groups that make up the area. Block groups used: 060816074002, 060816075001, 060816072002, 060816072001, 060816073002, 060816074003, 060816085014, 060816085011. Neighboring pages can share a block group, so their counts can overlap. Paid totals add building, contents and Increased Cost of Compliance payments and are not adjusted for inflation; a claim whose FEMA record shows a negative payment (an adjustment) counts as zero. Tree canopy: the mean of the 2025 NLCD Tree Canopy Cover values (0–100%, 30 m cells in an equal-area projection) for cells whose center lies inside the polygon. Fire hazard severity zones: the 2025 zone polygons (Local and State Responsibility Areas) intersected with the neighborhood polygon in an equal-area projection; the share of area in each class. FEMA National Risk Index: census tracts intersected with the polygon in an equal-area projection; each rating’s share is the share of the polygon covered by tracts with that rating (tracts covering less than 1% are left out; together the tracts used cover 100%). We do not compute a new score. Tracts used: 06081607500 (42%), 06081607200 (22%), 06081608501 (13%), 06081607400 (12%), 06081607300 (11%). See the methodology.
Sources
- Federal Emergency Management Agency (FEMA), FEMA OpenFEMA Dataset: FIMA NFIP Redacted Claims - v3. Retrieved on November 4, 2026.
- FEMA National Flood Hazard Layer (NFHL), Flood Hazard Zones and FIRM Panels. Retrieved on November 4, 2026.
- U.S. Census Bureau TIGERweb, 2010 Census Block Groups and U.S. Geological Survey, Geographic Names Information System (GNIS) domestic names.
- FEMA Glossary: Flood Zones.
- FloodSmart (NFIP): Buy a Flood Insurance Policy.
- FEMA Fact Sheet: Think you don’t need flood insurance? Think again (Jan. 21, 2025).
- 44 CFR 61.11, Effective date and time of coverage.
- OpenFEMA Terms and Conditions.
- USDA Forest Service. 2026. USFS NLCD Percent Tree Canopy CONUS v2025-6 (2025 map). Salt Lake City, UT (30 m cells; read November 4, 2026).
- National Weather Service: Heat Safety.
- U.S. EPA: Using Trees and Vegetation to Reduce Heat Islands.
- CAL FIRE Office of the State Fire Marshal, Fire Hazard Severity Zones (2025 maps; read November 4, 2026).
- FEMA National Risk Index, Census Tracts feature layer, Version 1.20.0 (December 2025) (retrieved November 4, 2026).
- FEMA OpenFEMA Dataset: FIMA NFIP Redacted Policies - v3.
- OpenFEMA NFIP Redacted Policies v3.
- OpenFEMA NFIP Redacted Claims v3.
- Fire Hazard Severity Zones.
- USDA Forest Service, Wildfire Risk to Communities, community summaries.
- Wildfire Risk to Communities methods.
- U.S. Census Bureau TIGERweb, Transportation (primary, secondary and local roads).
Data as of September 8, 2026 (FEMA claims) and November 4, 2026 (flood zones); hazard data computed November 4, 2026. Page last updated November 4, 2026.