Flooding in New Milford, New Jersey: the flood zone, the record, and what to do
Only about one eighth of New Milford is mapped as flood zone, yet the borough has the heaviest flood insurance record on the Hackensack River. The reason lies a short way upstream, at the Oradell Reservoir.
The Bergen County 2026 hazard mitigation plan puts 13.80 per cent of New Milford in the FEMA 1 per cent annual chance flood zone. Within that strip FEMA counts 824 National Flood Insurance Program claims and 140 repetitive-loss properties, 67 of them severe repetitive loss. The floods come from the Hackensack below the Oradell Reservoir, which holds water for supply rather than flood control.
The short version
- The Bergen County 2026 hazard plan maps 13.80 per cent of New Milford in the 1 per cent annual chance flood zone.
- FEMA records 824 flood insurance claims in New Milford, including 237 in 2011, and 140 repetitive-loss properties, 67 severe.
- The weather service names Columbia Street, Harvard Street, Pine Avenue and Lenox Avenue at every flood stage on the New Milford gauge.
- The flood of record is 12.36 feet on 16 April 2007; the gauge itself went under.
- FEMA says the lower Hackensack floods when Oradell Reservoir is high; the dam was built for water supply.
A heavy record in a narrow strip
FEMA's OpenFEMA data show 824 National Flood Insurance Program claims for the Borough of New Milford. Counted by ZIP code 07646 instead, as on our New Milford help page, the figure is 822; the two counts group a few claims differently. The worst year was 2011, with 237 claims, followed by 2007 with 155, 2021 with 94 and 1999 with 90. FEMA ties 170 claims to Hurricane Irene, 153 to the April 2007 nor'easter, 94 to Ida and 87 to Floyd. The US Census Bureau counts 6,376 housing units, so the claim total amounts to more than one for every eight homes, and in practice far more for the streets by the river. FEMA's multiple-loss records, as of 2 August 2026, list 140 repetitive-loss properties in New Milford, 67 of them severe repetitive loss, and the county plan names the borough as one of the places where repetitive losses concentrate. The county plan's own repetitive-loss table records no New Milford properties as mitigated.
Where the zone is
Table 4.6-1 of the county hazard plan counts 204.99 of New Milford's 1,485.29 acres in the 1 per cent annual chance flood zone, or 13.80 per cent, and 16.85 per cent including the 0.2 per cent zone. The zone follows the Hackensack River, which forms the borough's western side, and the lower reach of Hirschfeld Brook; FEMA's flood study models that brook's flood levels in New Milford with the Hackensack's backwater as the control. The study also describes a natural dike and berm system along the Hackensack River Bypass, created by excavating away from the river edge. It does not have a continuous elevation, FEMA says, and is subject to overtopping in the 1 per cent annual chance flood.
The gauge and the streets it names
The USGS gauge Hackensack River at New Milford drains 113 square miles, and USGS notes that flow there is regulated by four water-supply reservoirs, the last of them Oradell. The National Weather Service sets action stage at 5.5 feet, minor flooding at 6, moderate at 8 and major at 10. Its impact statements name the same New Milford streets at each step. At 6 feet there is minor flooding along Columbia Street, Harvard Street, Pine Avenue and Lenox Avenue, and water reaches River Edge Road to River Road and New Milford Avenue. At 8 feet water gets into homes on those four streets. At 10 feet the weather service expects home evacuations, with River Edge Road to River Road and New Milford Avenue closed.
The floods on record
The flood of record is 16 April 2007, when the river reached 12.36 feet and 11,600 cubic feet per second, a flow FEMA describes as much higher than the estimated 1 per cent annual chance peak. USGS reported that the gauge stopped operating in that flood when water submerged the equipment in its gagehouse, and that the peak was 0.98 feet above the previous record. That previous record, 11.45 feet, was set by Floyd on 16 September 1999. Irene in 2011 does not appear in the weather service's crest list, but FEMA puts its flow second only to 2007, at 10,500 cubic feet per second, and Irene produced more New Milford claims than any other storm. Lower crests are frequent: 8.23 feet in May 1989, 7.96 in April 1984 and 7.68 in March 2010 all passed moderate flood stage.
A water-supply dam, not a flood dam
FEMA's flood study states that the lower Hackensack floods when Oradell Reservoir is at a high stage. It gives the spillway crest as 22.7 feet and records a peak reservoir level of 26.2 feet on 17 September 1999, more than a foot above the previous record. After flooding in April 2022, the state environmental department said, as reported by CBS New York, that the reservoir serves for water supply and the dam was not built for flood control. For New Milford that means a big storm arriving when the reservoir is already full passes almost straight through to the river below.
What the borough says it can do
New Milford's entry in the county mitigation strategy is unusually frank. It says the borough has flooded many times, that most of the mitigation it needs is very expensive, and that it continually looks for funding. It wants to raise roadways along evacuation routes because residents are stranded before and during storms, but notes that this involves several municipalities, utilities and the purchase of many buildings. Elevating homes, it says, seems the best route, because the borough then keeps the family and its tax base. It also reports replacing storm piping with municipal funds and grants.
What this means if you own or rent here
Check your address on the FEMA Flood Map Service Center. If you live near the river, bookmark the weather service page for the New Milford gauge and learn the stage at which your street appears; when a forecast crest nears 6 feet, move cars off the low streets and lift basement contents, and leave before roads such as New Milford Avenue close. If your home has flooded more than once, ask the borough about elevation and any grant funding. About 38.6 per cent of households rent, according to the US Census Bureau, and tenants need their own contents cover. Flood insurance is a separate policy that normally takes 30 days to start, and whether a loss is covered is decided by your insurer and your policy wording.
Common questions
Does New Milford, NJ flood?
Its riverside streets do, repeatedly. FEMA counts 824 flood insurance claims and 140 repetitive-loss properties in the borough, almost all from the Hackensack River. Most of New Milford, about 86 per cent of its land, is outside the mapped 1 per cent annual chance flood zone.
Which streets flood first in New Milford?
National Weather Service impact statements for the New Milford gauge name Columbia Street, Harvard Street, Pine Avenue and Lenox Avenue, with water also reaching River Edge Road to River Road and New Milford Avenue, at 6 feet. Water enters homes on those streets at 8 feet.
Does the Oradell Reservoir protect New Milford?
No. The reservoir is operated for water supply. FEMA notes that the river below floods when the reservoir is at a high stage, and the state environmental department has said the dam was not built for flood control.
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