Photo: Gary gary gary at en.wikipedia · CC BY 3.0On FEMA’s figures, Hillsborough faces more hazard damage per building than 88% of U.S. towns, mostly from earthquakes
On FEMA’s National Risk Index, Hillsborough gets a D for hazard risk: higher expected damage per building than 88% of U.S. towns, #279 of 847 in California. Most of that expected damage is earthquakes (55%), then river and rain flooding (44%). Flood insurance has paid 8 claims here since 1993.
Graded on FEMA’s expected yearly building damage per dollar of building value (NRI v1.20, December 2025), weighted by where residents live; flood claims are shown, not graded. How hazard risk is graded
What Hillsborough faces
Each hazard’s share of the building damage FEMA expects here, and how its rate compares with the rest of the country.
Earthquakes
River and rain flooding
Shares are of FEMA’s expected building damage, the measure the grade uses; ranks compare each hazard’s building-damage rate with all 85,154 U.S. census tracts. In FEMA’s terms, river and rain flooding is FEMA’s “Inland Flooding” (rivers and streams overflowing their banks, or rain overwhelming drainage). FEMA defines coastal flooding as high or rising tides and storm surge, so surge damage is counted there. Drought isn’t listed: FEMA counts its losses in crops only.
What’s behind Hillsborough’s grade
Earthquakes are 55% of the building damage FEMA expects in Hillsborough, and Hillsborough’s rate of earthquakes damage is in the top 7% of U.S. census tracts. Next is river and rain flooding at 44% (higher than 71% of U.S. census tracts).
D #279 of 847 in California; higher expected damage per building than 88% of U.S. towns (21,298).
Hillsborough’s residents live in 2 census tracts; FEMA’s figures are combined by where they live.
The typical California town has higher expected damage than 92% of U.S. towns; within the state, Hillsborough has less expected damage per building than 67% of California towns.
In dollars, FEMA expects about $13.8M a year in losses across Hillsborough: $12.8M to buildings, the rest to people and crops.
Does Hillsborough flood? Rarely: 8 flood claims since 1993
Every paid claim on a federal flood insurance policy in Hillsborough, from FEMA’s records: 2.1 per 1,000 homes, fewer than 60% of the 13,809 U.S. towns with a flood insurance record.
- The Pineapple Express - Southern2 claims · $8K
- The California Atmospheric River2 claims · $52K
Hillsborough isn’t in FEMA’s Community Rating System, which cuts flood insurance up to 45% in towns that do extra flood-proofing.
Insurance rates: San Mateo County.4 federal disasters brought FEMA money to Hillsborough
Disasters that paid out in Hillsborough itself (aid to households or repair grants to the Town of Hillsborough), newest first, with that year’s flood claims.
- 2022Severe Winter Storms, Flooding, Landslides, and Mudslides29 households applied for aid$124K aid approved$1.7M to the Town of Hillsborough for repairs1 flood claim paid that year
- 2020Wildfires23 households applied for aid$4K aid approved
- 2006Severe Storms, Flooding, Landslides, and Mudslides$80K to the Town of Hillsborough for repairs
- 2005Severe Storms, Flooding, Mudslides, and Landslides$49K to the Town of Hillsborough for repairs
San Mateo County has had 19 natural disasters declared by the President since 1953, most often severe storms, then floods. Not counted: the 2005 Hurricane Katrina evacuee emergency, which covered counties that took in evacuees.
Also 2 FEMA wildfire suppression grants (Fire Management Assistance, not a disaster declaration) for fires in San Mateo County, 2010–2020.
Old photos of Hillsborough after a storm or flood belong in the town’s history. Add one, or share what you remember below.
Add to the Hillsborough archive →Hillsborough and its neighbors
Hillsborough is 2nd of the 5 graded towns here, from least expected damage per building to most. Tap a town to see its hazards.
| Town | Hazard risk | Mostly (buildings) | Flood claims |
|---|---|---|---|
| Baywood Park | C−more damage than 85% | earthquakes | — |
| Hillsborough | Dmore damage than 88% | earthquakes | 8 |
| Highlands | Dmore damage than 90% | earthquakes | — |
| Burlingame | Dmore damage than 94% | earthquakes | 65 |
| San Mateo | D−more damage than 95% | earthquakes | 49 |
Hazard risk = FEMA’s expected yearly building damage per dollar of building value, vs. the 21,298 U.S. towns we grade; the map is shaded by fifths of the same scale. Flood claims = paid federal flood insurance claims on record.
Get ready for what Hillsborough faces
A short kit for the hazards that drive the building damage here, what to check before you buy, and where neighbors get alerts.
- Drop, cover and hold on.
- Strap tall furniture and the water heater to the wall.
- Know how to shut off the gas.
- Turn around at flooded roads: a foot of moving water can carry off a car.
- Flood insurance usually takes 30 days to start, so buy it before the forecast.
- Keep papers and medicines up high, in a grab-and-go bag.
- Look up the address on FEMA’s flood map.
- Ask the seller or landlord whether it has ever flooded, and what flood insurance costs there.
- Get a flood insurance quote early: policies usually start 30 days after you buy.
Know where neighbors sign up for alerts? Add it to the Handbook so everyone has it.
Questions about natural hazards in Hillsborough
Is Hillsborough at risk for natural disasters?
On FEMA’s National Risk Index, Hillsborough has higher expected damage per building than 88% of U.S. towns: D for hazard risk, #279 of 847 in California. Most of the expected damage is earthquakes (55%) and river and rain flooding (44%). This is FEMA’s model of an average year for today’s buildings, not a forecast.
Does Hillsborough flood?
Flood insurance has paid 8 claims in Hillsborough since 1993, $125K in all, or 2.1 per 1,000 homes, fewer than 60% of U.S. towns with a flood insurance record. 1 properties have flooded more than once. The most claims came from Pineapple Express - Southern (2).
Is Hillsborough in a flood zone?
Flood zones are drawn street by street, so the answer depends on the address: look it up on FEMA’s flood map. In San Mateo County, 31% of homes in mapped flood zones carry federal flood insurance, and 1.8% of all homes do.
How much is flood insurance in Hillsborough?
FEMA’s Community Rating System list shows no discount for Hillsborough’s flood program. Premiums depend on the building; policies usually start 30 days after you buy, so get a quote early.
What was the biggest storm in Hillsborough?
By FEMA money that reached Hillsborough, Severe Winter Storms, Flooding, Landslides, and Mudslides (2022): 29 households applied for aid, $124K approved, and $1.7M to the Town of Hillsborough for repairs. By flood claims, Pineapple Express - Southern: 2 paid, $8K.
Is Hillsborough at risk from earthquakes?
It is the largest share of the building damage FEMA expects here (55%), and Hillsborough’s rate for it is in the top 7% of U.S. census tracts.
Storm stories
Memories, warnings and help from neighbors in Hillsborough.
Sources: FEMA National Risk Index v1.20 (December 2025), census-tract table, combined by where Hillsborough’s residents lived in the 2020 census; OpenFEMA: NFIP redacted claims, multiple-loss properties, community status book and residential penetration rates, housing assistance (owners and renters), public assistance funded projects, hazard mitigation properties and disaster declarations. Homes: Census ACS 2020–24. Preparedness tips: Ready.gov. FEMA’s model is an average of expected damage, not a forecast. How hazard risk is graded.