Marsh-Johnson House · Photo: Bill Fitzpatrick · CC BY-SA 3.0On FEMA’s figures, Johnston faces less hazard damage per building than 85% of U.S. towns, mostly from river and rain flooding
On FEMA’s National Risk Index, Johnston gets an A for hazard risk: lower expected damage per building than 85% of U.S. towns. Most of that expected damage is river and rain flooding (60%), then earthquakes (16%). 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 Johnston 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
Earthquakes
Hurricanes
Tornadoes
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 Johnston’s grade
River and rain flooding is 60% of the building damage FEMA expects in Johnston, and Johnston’s rate of river and rain flooding damage is lower than 84% of U.S. census tracts. Ice storms add 3%, at a rate in the top 9% of U.S. census tracts.
A lower expected damage per building than 85% of U.S. towns (21,298).
All of Johnston’s residents live in one census tract; the figures are that tract’s.
In dollars, FEMA expects about $567K a year in losses across Johnston: $272K to buildings, the rest to people and crops.
Does Johnston flood? No paid flood claims on record
FEMA’s records show no paid flood insurance claims in Johnston. That’s not a promise: most homes don’t carry flood insurance, so small floods go unrecorded.
Johnston isn’t in FEMA’s Community Rating System, which cuts flood insurance up to 45% in towns that do extra flood-proofing.
Insurance rates: Edgefield County.2 federal disasters brought FEMA money to Johnston
Disasters that paid out in Johnston itself (aid to households or repair grants to the Town of Johnston), newest first, with that year’s flood claims.
- 2024Hurricane Helene1,555 households applied for aid$1.3M aid approved$7K to the Town of Johnston for repairs
- 2004Severe Ice Storm$27K to the Town of Johnston for repairs
Edgefield County has had 15 natural disasters declared by the President since 1953, most often hurricanes and tropical storms, then winter storms. Not counted: the 2005 Hurricane Katrina evacuee emergency, which covered counties that took in evacuees.
Old photos of Johnston after a storm or flood belong in the town’s history. Add one, or share what you remember below.
Add to the Johnston archive →Get ready for what Johnston 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.
- Drop, cover and hold on.
- Strap tall furniture and the water heater to the wall.
- Know how to shut off the gas.
- 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.
- Pick your spot now: the lowest floor, an inside room, no windows.
- A watch means be ready; a warning means take cover now.
- Keep shoes and a flashlight by the bed.
- 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 Johnston
Is Johnston at risk for natural disasters?
On FEMA’s National Risk Index, Johnston has lower expected damage per building than 85% of U.S. towns: A for hazard risk. Most of the expected damage is river and rain flooding (60%) and earthquakes (16%). The figures are for the one census tract the town shares with its neighbors. This is FEMA’s model of an average year for today’s buildings, not a forecast.
Is Johnston 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 Edgefield County, 0.4% of all homes carry federal flood insurance.
How much is flood insurance in Johnston?
FEMA’s Community Rating System list shows no discount for Johnston’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 Johnston?
By FEMA money that reached Johnston, Hurricane Helene (2024): 1,555 households applied for aid, $1.3M approved, and $7K to the Town of Johnston for repairs.
Is Johnston at risk from river and rain flooding?
It is the largest share of the building damage FEMA expects here (60%), and Johnston’s rate for it is lower than 84% of U.S. census tracts.
Storm stories
Memories, warnings and help from neighbors in Johnston.
Sources: FEMA National Risk Index v1.20 (December 2025), census-tract table, combined by where Johnston’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.