USS ARIZONA Wreck · Photo: Robert Enrique Muller · Public domainOn FEMA’s figures, Waimalu faces more hazard damage per building than 73% of U.S. towns, mostly from river and rain flooding
On FEMA’s National Risk Index, Waimalu gets a C for hazard risk: higher expected damage per building than 73% of U.S. towns, #1 of 93 in Hawaii. Most of that expected damage is river and rain flooding (72%), then earthquakes (19%). Flood insurance has paid 1 claim here since 1991.
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 Waimalu 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
Wildfire
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 Waimalu’s grade
River and rain flooding is 72% of the building damage FEMA expects in Waimalu, and Waimalu’s rate of river and rain flooding damage is higher than 79% of U.S. census tracts. Wildfire adds 6%, at a rate in the top 5% of U.S. census tracts.
C #1 of 93 in Hawaii; higher expected damage per building than 73% of U.S. towns (21,298).
Waimalu’s residents live in 4 census tracts; FEMA’s figures are combined by where they live.
The typical Hawaii town has higher expected damage than 96% of U.S. towns; within the state, Waimalu has less expected damage per building than 100% of Hawaii towns.
In dollars, FEMA expects about $4.4M a year in losses across Waimalu: $3.7M to buildings, the rest to people and crops.
Does Waimalu flood? Rarely: 1 flood claim since 1991
Every paid claim on a federal flood insurance policy in Waimalu, from FEMA’s records: 0.2 per 1,000 homes, fewer than 98% of the 13,809 U.S. towns with a flood insurance record.
Waimalu isn’t in FEMA’s Community Rating System, which cuts flood insurance up to 45% in towns that do extra flood-proofing.
Insurance rates: Honolulu County.The storms Waimalu remembers
None of the 18 disasters declared for Honolulu County shows FEMA aid or repair money reaching Waimalu itself in FEMA’s records, so these are its biggest flood-claim years.
- 19911 flood claims paidNo declaration for the county that year
Honolulu County has had 18 natural disasters declared by the President since 1953, most often severe storms, then floods.
Also 4 FEMA wildfire suppression grants (Fire Management Assistance, not a disaster declaration) for fires in Honolulu County, 2005–2025.
Old photos of Waimalu after a storm or flood belong in the town’s history. Add one, or share what you remember below.
Add to the Waimalu archive →Waimalu and its neighbors
Waimalu has the lowest expected damage per building of the 3 graded towns here. Tap a town to see its hazards.
| Town | Hazard risk | Mostly (buildings) | Flood claims |
|---|---|---|---|
| Waimalu | Cmore damage than 73% | river and rain flooding | 1 |
| Aiea | Cmore damage than 73% | river and rain flooding | 3 |
| Pearl City | C−more damage than 80% | river and rain flooding | 1 |
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 Waimalu 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.
- Clear dead leaves and brush within 5 feet of the house.
- Sign up for local alerts and know two ways out.
- Keep N95 masks for smoky days.
- 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 Waimalu
Is Waimalu at risk for natural disasters?
On FEMA’s National Risk Index, Waimalu has higher expected damage per building than 73% of U.S. towns: C for hazard risk, #1 of 93 in Hawaii. Most of the expected damage is river and rain flooding (72%) and earthquakes (19%). This is FEMA’s model of an average year for today’s buildings, not a forecast.
Does Waimalu flood?
Flood insurance has paid 1 claim in Waimalu since 1991, $11K in all, or 0.2 per 1,000 homes, fewer than 98% of U.S. towns with a flood insurance record.
Is Waimalu 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 Honolulu County, 54% of homes in mapped flood zones carry federal flood insurance, and 4.1% of all homes do.
How much is flood insurance in Waimalu?
FEMA’s Community Rating System list shows no discount for Waimalu’s flood program. Premiums depend on the building; policies usually start 30 days after you buy, so get a quote early.
Is Waimalu at risk from river and rain flooding?
It is the largest share of the building damage FEMA expects here (72%), and Waimalu’s rate for it is higher than 79% of U.S. census tracts.
Storm stories
Memories, warnings and help from neighbors in Waimalu.
Sources: FEMA National Risk Index v1.20 (December 2025), census-tract table, combined by where Waimalu’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.