FEMA puts Union Mill’s expected hazard damage per building below that of 62% of U.S. towns, mostly from river and rain flooding
On FEMA’s National Risk Index, Union Mill gets a B for hazard risk: lower expected damage per building than 62% of U.S. towns, #191 of 253 in Virginia. Most of that expected damage is river and rain flooding (88%). FEMA’s files show no paid flood insurance claims here.
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 Union Mill faces
Each hazard’s share of the building damage FEMA expects here, and how its rate compares with the rest of the country.
River and rain flooding
Hurricanes
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 Union Mill’s grade
River and rain flooding is 88% of the building damage FEMA expects in Union Mill, and Union Mill’s rate of river and rain flooding damage is higher than 63% of U.S. census tracts. Next is hurricanes at 6% (higher than 72% of U.S. census tracts).
B #191 of 253 in Virginia; lower expected damage per building than 62% of U.S. towns (21,298).
Union Mill’s residents live in 4 census tracts; FEMA’s figures are combined by where they live.
The typical Virginia town has lower expected damage than 81% of U.S. towns; within the state, Union Mill has more expected damage per building than 75% of Virginia towns.
In dollars, FEMA expects about $1.9M a year in losses across Union Mill: $1.8M to buildings, the rest to people and crops.
Does Union Mill flood? No paid flood claims on record
FEMA’s records show no paid flood insurance claims in Union Mill. That’s not a promise: most homes don’t carry flood insurance, so small floods go unrecorded.
Union Mill isn’t in FEMA’s Community Rating System, which cuts flood insurance up to 45% in towns that do extra flood-proofing.
Insurance rates: Fairfax County.The storms Union Mill remembers
None of the 16 disasters declared for Fairfax County shows FEMA aid or repair money reaching Union Mill itself in FEMA’s records, so these are its biggest flood-claim years.
Fairfax County has had 16 natural disasters declared by the President since 1953, most often winter storms, then hurricanes and tropical storms. Not counted: the 2005 Hurricane Katrina evacuee emergency, which covered counties that took in evacuees.
Union Mill and its neighbors
Union Mill is 4th 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 |
|---|---|---|---|
| Fairfax Station | A−less damage than 79% | river and rain flooding | 5 |
| Fair Lakes | B+less damage than 72% | river and rain flooding | — |
| Braddock | B+less damage than 67% | river and rain flooding | 7 |
| Union Mill | Bless damage than 62% | river and rain flooding | 0 |
| Centreville | B−less damage than 54% | river and rain flooding | 12 |
| Clifton | — | 312 residents; we grade 1,000+ | |
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 Union Mill faces
A short kit for the hazards that drive the building damage here, what to check before you buy, and where neighbors get alerts.
- 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.
- The season runs June through November and peaks from mid-August to mid-October.
- Bring in porch furniture and anything the wind can throw.
- Fill the gas tank and charge phones before the storm arrives.
- 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 Union Mill
Is Union Mill at risk for natural disasters?
On FEMA’s National Risk Index, Union Mill has lower expected damage per building than 62% of U.S. towns: B for hazard risk, #191 of 253 in Virginia. Most of the expected damage is river and rain flooding (88%) and hurricanes (6%). This is FEMA’s model of an average year for today’s buildings, not a forecast.
Is Union Mill 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 Fairfax County, 22% of homes in mapped flood zones carry federal flood insurance, and 1.1% of all homes do.
How much is flood insurance in Union Mill?
FEMA’s Community Rating System list shows no discount for Union Mill’s flood program. Premiums depend on the building; policies usually start 30 days after you buy, so get a quote early.
Is Union Mill at risk from river and rain flooding?
It is the largest share of the building damage FEMA expects here (88%), and Union Mill’s rate for it is higher than 63% of U.S. census tracts.
Storm stories
Memories, warnings and help from neighbors in Union Mill.
Sources: FEMA National Risk Index v1.20 (December 2025), census-tract table, combined by where Union Mill’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.