Warren County, NJ: flood zone, zoning and property lines by address
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Towns in Warren County: Phillipsburg, Hackettstown, Washington.
Flood zone by address
ParcelSheet reads FEMA's National Flood Hazard Layer at the lot: the zone, whether it is a high risk area where lenders ask for flood insurance, and the base flood elevation where FEMA lists one. FEMA's countywide study for Warren County has 126 FIRM panels, the newest effective September 2011; no coastal V zones are mapped in it.
The official panel and any Letter of Map Amendment are at FEMA's Map Service Center. An elevation certificate for a Warren house comes from a licensed surveyor and is often on file with the county or city building office.
Property lines
The parcel outline, parcel number and mapped size come from the New Jersey statewide parcel map (NJ Office of GIS cadastral layer with the MOD-IV tax list), so a Warren lot shows the same lines the municipal tax maps draw. Warren County covers about 228,186 acres of land and 3,910 acres of water.
Mapped lines are approximate. The Warren County Board of Taxation keeps the parcel record (Warren County website); every county's office is on the state's county boards of taxation list; a licensed surveyor sets the true corners.
Zoning
In New Jersey zoning is set by each municipality, not by the county: in Warren County, Phillipsburg, Hackettstown, Washington each zone the land inside their limits. ParcelSheet shows the use code on the lot's parcel record and the municipality it sits in; the municipal zoning office has the district, the uses it allows and the lot size it needs. The Warren County website lists the county's municipalities.
ADU and guest houses
The New Jersey Municipal Land Use Law (N.J.S.A. 40:55D) lets each municipality allow an accessory dwelling unit on a lot with a house. Whether a Warren lot can add one depends on its district; the municipal zoning office has the rule. ParcelSheet shows the mapped lot size and the ground's slope, the first two things the question turns on.
Septic and soil
ParcelSheet reads the USDA soil survey at the lot: the soil's name, its septic absorption rating and whether it is prime farmland. Warren County is soil survey area NJ041, Warren County, New Jersey, last updated August 2026, on Web Soil Survey.
A new or changed septic system in Warren County needs a permit from the Warren County health department under the NJDEP septic rules (N.J.A.C. 7:9A), which tests the soil on the lot itself.
Setbacks
Setbacks in Warren County come from the zoning district: the front, side and rear distances a house must keep. ParcelSheet does not draw setback lines; the municipal zoning office gives them for the lot's district, and Phillipsburg, Hackettstown, Washington for land inside their limits.
Hazards that apply
- Wetlands and wildfire. ParcelSheet shows the National Wetlands Inventory near a Warren lot and the Forest Service wildfire hazard rating at it.
Questions
Is my house in a flood zone in Warren County?
Type the address in the box above and ParcelSheet reads FEMA's flood zone at the lot's center. FEMA's countywide flood map for Warren County has 126 panels, the newest effective September 2011. A lender or insurer uses the official FIRM panel; FEMA's Map Service Center has it.
How do I find property lines in Warren County?
Open the New Jersey map, type the address, and the parcel outline from the county Board of Taxation shows on the map with its parcel number and mapped size. Mapped lines are approximate; only a licensed surveyor sets the true corners.
What is my property zoned in Warren County?
Zoning in Warren County is set by each municipality (such as Phillipsburg, Hackettstown), not by the county. ParcelSheet shows the use code on the parcel record and names the municipality; the municipal zoning office has the final word.
Can I build an ADU in Warren County?
The New Jersey Municipal Land Use Law (N.J.S.A. 40:55D) lets each municipality allow an accessory dwelling unit, and each sets its own rules. In Warren County ask the municipal zoning office for the lot's district first; ParcelSheet shows the lot size as mapped so you can see the room you have.
Do I need a septic permit in Warren County?
Yes. A new or changed septic system in Warren County needs a permit from the Warren County health department under the NJDEP septic rules (N.J.A.C. 7:9A). ParcelSheet shows the USDA soil survey's septic rating at the lot, from survey area NJ041 (Warren County, New Jersey).
Next to Warren County: Hunterdon County, Morris County, Sussex County.
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