FEMA expects more hazard damage per building in Waipio Acres than almost anywhere in the U.S., mostly from river and rain flooding
On FEMA’s National Risk Index, Waipio Acres gets a D− for hazard risk: among the highest expected damage per building of U.S. towns, #81 of 93 in Hawaii. Most of that expected damage is river and rain flooding (94%). 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 Waipio Acres 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
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 Waipio Acres’ grade
River and rain flooding is 94% of the building damage FEMA expects in Waipio Acres, and Waipio Acres’ rate of river and rain flooding damage is in the top 1% of U.S. census tracts. Wildfire adds 2%, at a rate in the top 5% of U.S. census tracts.
D− #81 of 93 in Hawaii; among the highest expected damage per building of U.S. towns (21,298).
Waipio Acres’ residents live in 2 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, Waipio Acres has more expected damage per building than 87% of Hawaii towns.
In dollars, FEMA expects about $3.6M a year in losses across Waipio Acres: $3.4M to buildings, the rest to people and crops.
Does Waipio Acres flood? No paid flood claims on record
FEMA’s records show no paid flood insurance claims in Waipio Acres. That’s not a promise: most homes don’t carry flood insurance, so small floods go unrecorded.
Waipio Acres 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 Waipio Acres remembers
None of the 18 disasters declared for Honolulu County shows FEMA aid or repair money reaching Waipio Acres itself in FEMA’s records, so these are its biggest flood-claim years.
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.
Waipio Acres and its neighbors
Waipio Acres is 3rd of the 3 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 |
|---|---|---|---|
| Mililani Mauka | D−more damage than 97% | river and rain flooding | — |
| Mililani Town | D−more damage than 98% | river and rain flooding | — |
| Waipio Acres | D−among the highest damage | river and rain flooding | 0 |
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 Waipio Acres 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.
- 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 Waipio Acres
Is Waipio Acres at risk for natural disasters?
On FEMA’s National Risk Index, Waipio Acres has among the highest expected damage per building of U.S. towns: D− for hazard risk, #81 of 93 in Hawaii. Most of the expected damage is river and rain flooding (94%). This is FEMA’s model of an average year for today’s buildings, not a forecast.
Is Waipio Acres 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 Waipio Acres?
FEMA’s Community Rating System list shows no discount for Waipio Acres’ flood program. Premiums depend on the building; policies usually start 30 days after you buy, so get a quote early.
Is Waipio Acres at risk from river and rain flooding?
It is the largest share of the building damage FEMA expects here (94%), and Waipio Acres’ rate for it is in the top 1% of U.S. census tracts.
Storm stories
Memories, warnings and help from neighbors in Waipio Acres.
Sources: FEMA National Risk Index v1.20 (December 2025), census-tract table, combined by where Waipio Acres’ 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.