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DAVID THOMPSON HOUSEPhoto: JERRYE & ROY KLOTZ MD · CC BY-SA 3.0
B+Hazard risk
Natural hazards in Mendham · FEMA

FEMA puts Mendham’s expected hazard damage per building below that of 68% of U.S. towns, mostly from river and rain flooding

On FEMA’s National Risk Index, Mendham gets a B+ for hazard risk: lower expected damage per building than 68% of U.S. towns, #113 of 468 in New Jersey. Most of that expected damage is river and rain flooding (88%). Flood insurance has paid 1 claim here since 2011.

River and rain flooding 88%Hurricanes 5%Earthquakes 3%

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

less than 68%of U.S. townsLess damageMoreExpected yearly damage per dollar of building, vs. the 21,298 U.S. towns we grade#113 of 468 in New Jersey
Hazard risk
B+#113 of 468
in New Jersey · lower than 68% of U.S. towns
Main hazard
River and rain flooding
88% of expected building damage
Flood claims
1
paid since 2011 · $31K
Disasters paid out here
10
of 25 declared for Morris County
By hazard

What Mendham 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

88%of expected building damage
About average · higher than 59% of U.S. census tracts
Recorded about 4 times a year in the area
Smaller shares here
 Hurricanes Earthquakes Tornadoes Strong wind Winter storms Hail Lightning Wildfire Ice storms Cold waves Heat waves Landslides
FEMA models no building damage here
Coastal floodingAvalanchesTsunamisVolcanic activity

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.

Flood risk changes street by street. Check a specific address on FEMA’s flood map, and ask about flood insurance before you buy.
Hazard risk grade

What’s behind Mendham’s grade

River and rain flooding is 88% of the building damage FEMA expects in Mendham, and Mendham’s rate of river and rain flooding damage is higher than 59% of U.S. census tracts.

Where Mendham sits
Mendham
Least damageMiddleMost damage

B+ #113 of 468 in New Jersey; lower expected damage per building than 68% of U.S. towns (21,298).

All of Mendham’s residents live in one census tract; the figures are that tract’s.

What drives the damage to buildings
River and rain flooding88%Hurricanes5%Everything else7%

The typical New Jersey town has higher expected damage than 56% of U.S. towns; within the state, Mendham has less expected damage per building than 76% of New Jersey towns.

In dollars, FEMA expects about $2.0M a year in losses across Mendham: $1.6M to buildings, the rest to people and crops.

Shared tract.All of Mendham’s 4,981 residents (2020 census) live in one census tract. FEMA publishes its model by tract, so the rate and the hazard mix are the tract’s. The flood claims below are the town’s own.
A shared figure. The grade describes the whole tract, not each street in it, and FEMA’s model is an average year for today’s buildings, not a record: the claims below are the record.

How TownRatings grades hazard risk →

Flood insurance claims

Does Mendham flood? Rarely: 1 flood claim since 2011

Every paid claim on a federal flood insurance policy in Mendham, from FEMA’s records: 0.5 per 1,000 homes, fewer than 88% of the 13,809 U.S. towns with a flood insurance record.

Paid flood claims, by year
2011: 1 claim2012: 0 claims2013: 0 claims2014: 0 claims2015: 0 claims2016: 0 claims2017: 0 claims2018: 0 claims2019: 0 claims2020: 0 claims2021: 0 claims2022: 0 claims2023: 0 claims2024: 0 claims2025: 0 claims2026: 0 claims2011
20112026
Biggest named events
  • Hurricane Irene1 claim · $31K
1
paid claims since 2011
$31K
paid to owners
0
homes flooded more than once
$31K
average claim
of all homes are insured
No community discount

Mendham isn’t in FEMA’s Community Rating System, which cuts flood insurance up to 45% in towns that do extra flood-proofing.

Insurance rates: Morris County.
Disasters

10 federal disasters brought FEMA money to Mendham

Disasters that paid out in Mendham itself (aid to households or repair grants to the Borough of Mendham), newest first, with that year’s flood claims.

  1. 2021Remnants of Hurricane Ida36 households applied for aid$47K aid approved$24K to the Borough of Mendham for repairs
  2. 2021Severe Winter Storm and Snowstorm$62K to the Borough of Mendham for repairs
  3. 2020Tropical Storm Isaias$150K to the Borough of Mendham for repairs
  4. 2018Severe Winter Storm and Snowstorm$58K to the Borough of Mendham for repairs
  5. 2016Severe Winter Storm and Snowstorm$19K to the Borough of Mendham for repairs
  6. 2012Hurricane Sandy116 households applied for aid$12K aid approved$352K to the Borough of Mendham for repairs
Show all 10
  1. 2011Severe Storm$146K to the Borough of Mendham for repairs
  2. 2011Hurricane Irene50 households applied for aid$70K aid approved$126K to the Borough of Mendham for repairs1 flood claim paid for it, $31K
  3. 2010Severe Storms and Flooding4 households applied for aid$2K aid approved
  4. 1999Hurricane Floyd Major Disaster Declarations$5K to the Borough of Mendham for repairs
Disasters declared, by decade
Paid out in MendhamMorris County only

Morris County has had 25 natural disasters declared by the President since 1953, most often severe storms, then hurricanes and tropical storms. Not counted: the 2005 Hurricane Katrina evacuee emergency, which covered counties that took in evacuees; the 2001 World Trade Center declarations.

Were you here?

Old photos of Mendham after a storm or flood belong in the town’s history. Add one, or share what you remember below.

Add to the Mendham archive →
Next door

Mendham and its neighbors

Mendham has the lowest expected damage per building of the 2 graded towns here. Tap a town to see its hazards.

Mendham Township: hazard risk C+Brookside: not gradedMendham TownshipBrooksideMendham
Lowest fifthSecondMiddleFourthHighest fifth
TownHazard riskMostly (buildings)Flood claims
MendhamB+less damage than 68%river and rain flooding1
Mendham TownshipC+more damage than 56%river and rain flooding22
Brookside—a Census area inside a town; graded with the town

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.

Be ready

Get ready for what Mendham faces

A short kit for the hazards that drive the building damage here, what to check before you buy, and where neighbors get alerts.

When the river rises
  • 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.
More from Ready.gov ↗
Before you buy or rent
  • 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.
When a storm is coming
Forecast and alertsWeather →911, the nearest ERSafety →

Know where neighbors sign up for alerts? Add it to the Handbook so everyone has it.

Questions about natural hazards in Mendham

Is Mendham at risk for natural disasters?

On FEMA’s National Risk Index, Mendham has lower expected damage per building than 68% of U.S. towns: B+ for hazard risk, #113 of 468 in New Jersey. Most of the expected damage is river and rain flooding (88%). 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.

Does Mendham flood?

Flood insurance has paid 1 claim in Mendham since 2011, $31K in all, or 0.5 per 1,000 homes, fewer than 88% of U.S. towns with a flood insurance record. The most claims came from Hurricane Irene (1).

Is Mendham 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 Morris County, 1.4% of all homes carry federal flood insurance.

How much is flood insurance in Mendham?

FEMA’s Community Rating System list shows no discount for Mendham’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 Mendham?

By FEMA money that reached Mendham, Hurricane Sandy (2012): 116 households applied for aid, $12K approved, and $352K to the Borough of Mendham for repairs. By flood claims, Hurricane Irene: 1 paid, $31K.

Is Mendham at risk from river and rain flooding?

It is the largest share of the building damage FEMA expects here (88%), and Mendham’s rate for it is higher than 59% of U.S. census tracts.

Storm stories

Memories, warnings and help from neighbors in Mendham.

Town Square →
Start the conversation

Sources: FEMA National Risk Index v1.20 (December 2025), census-tract table, combined by where Mendham’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.