Photo: Russ · CC BY 2.0FEMA expects less hazard damage per building in Potomac than in 96% of U.S. towns, mostly from river and rain flooding
On FEMA’s National Risk Index, Potomac gets an A+ for hazard risk: lower expected damage per building than 96% of U.S. towns, #144 of 261 in Maryland. Most of that expected damage is river and rain flooding (74%), then hurricanes (11%). Flood insurance has paid 30 claims here since 1979.
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 stands out about Potomac’s natural hazards
From FEMA’s model and FEMA’s records, below.
What Potomac 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
Earthquakes
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 Potomac’s grade
River and rain flooding is 74% of the building damage FEMA expects in Potomac, and Potomac’s rate of river and rain flooding damage is lower than 85% of U.S. census tracts. Next is hurricanes at 11% (higher than 71% of U.S. census tracts).
A+ #144 of 261 in Maryland; lower expected damage per building than 96% of U.S. towns (21,298).
Potomac’s residents live in 11 census tracts; FEMA’s figures are combined by where they live.
The typical Maryland town has lower expected damage than 97% of U.S. towns; within the state, Potomac has more expected damage per building than 55% of Maryland towns.
In dollars, FEMA expects about $9.6M a year in losses across Potomac: $8.3M to buildings, the rest to people and crops.
Does Potomac flood? Sometimes: 30 flood claims since 1979
Every paid claim on a federal flood insurance policy in Potomac, from FEMA’s records: 1.8 per 1,000 homes, fewer than 64% of the 13,809 U.S. towns with a flood insurance record.
- Hurricane Ida2 claims · $49K
Potomac isn’t in FEMA’s Community Rating System, which cuts flood insurance up to 45% in towns that do extra flood-proofing.
Insurance rates: Montgomery County.1 federal disaster brought FEMA money to Potomac
Disasters that paid out in Potomac itself (aid to households or repair grants to Potomac), newest first, with that year’s flood claims.
- 2003Hurricane Isabel18 households applied for aid$17K aid approved
Montgomery County has had 17 natural disasters declared by the President since 1953, most often winter storms, then severe storms. Not counted: the 2005 Hurricane Katrina evacuee emergency, which covered counties that took in evacuees.
Old photos of Potomac after a storm or flood belong in the town’s history. Add one, or share what you remember below.
Add to the Potomac archive →Potomac and its neighbors
Potomac is 4th of the 8 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 |
|---|---|---|---|
| Rockville | A+among the lowest damage | river and rain flooding | 11 |
| North Bethesda | A+among the lowest damage | river and rain flooding | 35 |
| Bethesda | A+less damage than 97% | river and rain flooding | 55 |
| Potomac | A+less damage than 96% | river and rain flooding | 30 |
| Cabin John | Aless damage than 94% | river and rain flooding | 15 |
| Travilah | Aless damage than 93% | river and rain flooding | 3 |
| McLean | Aless damage than 85% | river and rain flooding | 57 |
| Great Falls | A−less damage than 82% | river and rain flooding | 15 |
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 Potomac 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.
- Drop, cover and hold on.
- Strap tall furniture and the water heater to the wall.
- Know how to shut off the gas.
- 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 Potomac
Is Potomac at risk for natural disasters?
On FEMA’s National Risk Index, Potomac has lower expected damage per building than 96% of U.S. towns: A+ for hazard risk, #144 of 261 in Maryland. Most of the expected damage is river and rain flooding (74%) and hurricanes (11%). This is FEMA’s model of an average year for today’s buildings, not a forecast.
Does Potomac flood?
Flood insurance has paid 30 claims in Potomac since 1979, $577K in all, or 1.8 per 1,000 homes, fewer than 64% of U.S. towns with a flood insurance record. The most claims came from Hurricane Ida (2).
Is Potomac 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 Montgomery County, 51% of homes in mapped flood zones carry federal flood insurance, and 0.8% of all homes do.
How much is flood insurance in Potomac?
FEMA’s Community Rating System list shows no discount for Potomac’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 Potomac?
By FEMA money that reached Potomac, Hurricane Isabel (2003): 18 households applied for aid, $17K approved. By flood claims, Hurricane Ida: 2 paid, $49K.
Is Potomac at risk from river and rain flooding?
It is the largest share of the building damage FEMA expects here (74%), and Potomac’s rate for it is lower than 85% of U.S. census tracts.
Storm stories
Memories, warnings and help from neighbors in Potomac.
Sources: FEMA National Risk Index v1.20 (December 2025), census-tract table, combined by where Potomac’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.