Flooding in Leonia, New Jersey: the flood zone, the record, and what to do
On paper Leonia's flood risk is a neat strip along Overpeck Creek. In practice, the water that has damaged homes here in recent years has come down the hillside streets in cloudbursts, and the borough now treats stormwater as its first priority.
The Bergen County hazard mitigation plan puts 16.22 per cent of Leonia's land in the 1 per cent annual chance flood zone, almost all of it along Overpeck Creek on the borough's western edge. FEMA has recorded only 24 flood insurance claims in Leonia, but the heaviest year was 2024, and the borough has told the county that stormwater management is its most critical and urgent emergency issue. With some of the oldest housing in Bergen County, the basement is where most Leonia households will meet the problem.
The short version
- The county hazard plan puts 16.22 per cent of Leonia in the 1 per cent flood zone, almost all along Overpeck Creek.
- FEMA records 24 flood claims in Leonia; the heaviest year was 2024, with 7.
- FEMA lists 3 Leonia repetitive-loss properties, none severe, as of August 2026.
- The borough calls stormwater its most urgent issue and has hired NJIT to plan retention basins.
- The median Leonia home was built in 1945; only Bogota has older housing in Bergen County.
A flood zone with a sharp edge
The Bergen County 2026 Hazard Mitigation Plan counts about 169 of Leonia's 1,042 acres, or 16.22 per cent, inside FEMA's 1 per cent annual chance Special Flood Hazard Area. Unusually, adding the 0.2 per cent annual chance zone changes almost nothing: it contributes well under one acre. That is what you would expect where a flat creek valley meets a steep slope. The mapped zone follows Overpeck Creek along the western side of the borough, much of it beside Overpeck County Park, which Leonia helped create more than 50 years ago by donating land. Above that line the ground climbs east toward the Palisades ridge, and the official maps show little risk at all. FEMA's Flood Insurance Study covers Overpeck Creek and Flat Rock Brook in Leonia; a small stream once called Golf Course Creek, shared with Englewood, is now mapped as Flat Rock Brook Tributary 1.
Twenty-four claims, rising lately
FEMA's National Flood Insurance Program data, grouped by community, count 24 claims in Leonia over the life of the programme. The heaviest single year was 2024, with 7 claims, followed by 2021 with 5, 2011 with 4 and 1979 with 3. By named event, FEMA attributes 5 claims to Ida and 4 to Irene. Its multiple-loss records list 3 Leonia repetitive-loss properties as of 2 August 2026, none in the severe category. The county plan records 26 active flood insurance policies in the borough as of October 2024, against 3,598 housing units counted by the US Census Bureau. The numbers are small, but the direction matters: half of all Leonia claims have come since 2011, and the 2024 total came in the summer that two cloudbursts struck neighbouring Englewood.
Why stormwater, not the creek, is the borough's worry
In its section of the 2026 county plan, the Borough of Leonia states that stormwater mitigation is one of the most critical and urgent emergency situations it has to address and its top priority for the foreseeable future. It has set up a Flood Committee of the mayor, the council president, a councilman and the borough administrator, engaged NJIT to carry out a comprehensive hydraulic analysis that will identify the location and size of stormwater retention basins, applied for grant and congressional funding, and published a webpage on stormwater resilience for homeowners. Leonia is also one of the towns in the regional flooding and stormwater group that the City of Englewood convened in March 2024, alongside Englewood Cliffs, Fort Lee, Palisades Park and Teaneck. Water running off the ridge does not respect flood zone lines, and the claims bear that out.
Some of the oldest houses in the county
The US Census Bureau puts the median year built of Leonia's homes at 1945, tied with Rutherford and second only to Bogota among Bergen County municipalities. Houses of that age were built with basements meant for coal and storage, foundation walls that were never waterproofed to modern standards, and floor drains that often connect to old lateral pipes. When a storm overloads the street drains, water reaches these basements by three routes: through the walls and floor slab as the ground saturates, back up through floor drains and fixtures, and in through window wells and outside stairs as surface runoff. Each has a different fix. Telling them apart, by noticing where the water first appears, is the most useful thing an owner can do after a storm.
What this means if you own or rent here
If your home is near Overpeck Creek, check the FEMA Flood Map Service Center for your address. If it is up the slope, do not assume the map tells the whole story: FEMA notes that a large share of flood insurance claims come from outside high-risk zones. Keep gutters and the storm grate nearest your driveway clear, extend downspouts away from the foundation, and consider a backwater valve if water has ever come up through a floor drain. Read the borough's stormwater resilience guidance for homeowners. About 30 per cent of Leonia households rent, according to the US Census Bureau; a landlord's policy does not cover a tenant's belongings. Flood cover is a separate policy, and sewer backup is usually a separate endorsement. Whether a given loss is covered is decided by your insurer and your policy wording.
Common questions
Does Leonia, NJ flood?
Along Overpeck Creek, yes, and heavy rain also floods basements elsewhere in the borough. FEMA counts 24 flood insurance claims in Leonia, with the most in 2024. The borough describes stormwater as one of its most urgent problems.
How much of Leonia is in a flood zone?
The Bergen County 2026 Hazard Mitigation Plan puts 16.22 per cent of Leonia's land in the 1 per cent annual chance flood zone, mostly along Overpeck Creek. Check an individual address on the FEMA Flood Map Service Center.
What is Leonia doing about flooding?
According to the county plan, the borough formed a Flood Committee, commissioned an NJIT hydraulic analysis to site stormwater retention basins, applied for outside funding and published homeowner guidance on stormwater resilience.
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