Coos County, NH zoning map, flood zone and property lines by address
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Towns in Coos County: Berlin, Northumberland, Lancaster.
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 Coos County has 226 FIRM panels, the newest effective February 2013; 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 Coos 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 NH GRANIT parcel mosaic, from town parcel maps, so a Coos lot shows the same lines the town assessor draws. Coos County covers about 1,148,527 acres of land and 22,868 acres of water.
Mapped lines are approximate. The town assessors in Coos County keep the parcel record (Coos County website); a licensed surveyor sets the true corners.
Zoning
In New Hampshire zoning is set by each town and city, not by the county: in Coos County, Berlin zones the land inside its limits. ParcelSheet shows the use code on the lot's parcel record and the municipality it sits in; the town planning and zoning office has the district, the uses it allows and the lot size it needs. The Coos County website lists the county's municipalities.
ADU and guest houses
Under New Hampshire's municipal zoning law (RSA Chapter 674, starting at 674:16), each town and city can allow an accessory dwelling unit on a lot with a house. Whether a Coos lot can add one depends on its district; the town planning and 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. Coos County is soil survey area NH607, Coos County Area, New Hampshire, last updated August 2026, on Web Soil Survey.
A new or changed septic system in Coos County needs a state construction approval from the New Hampshire Department of Environmental Services Subsurface Systems Bureau.
Setbacks
Setbacks in Coos County come from the zoning district: the front, side and rear distances a house must keep. ParcelSheet does not draw setback lines; the town planning and zoning office gives them for the lot's district, and Berlin for land inside its limits.
Hazards that apply
- Wetlands and wildfire. ParcelSheet shows the National Wetlands Inventory near a Coos lot and the Forest Service wildfire hazard rating at it.
Questions
Is my house in a flood zone in Coos 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 Coos County has 226 panels, the newest effective February 2013. A lender or insurer uses the official FIRM panel; FEMA's Map Service Center has it.
How do I find property lines in Coos County?
Open the New Hampshire map, type the address, and the parcel outline from the town assessors in Coos County 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 Coos County?
Zoning in Coos County is set by each town and city (such as Berlin), not by the county. ParcelSheet shows the use code on the parcel record and names the municipality; the town planning and zoning office has the final word.
Can I build an ADU in Coos County?
Under New Hampshire's municipal zoning law (RSA Chapter 674, starting at 674:16), each town and city can allow an accessory dwelling unit, and each sets its own rules. In Coos County ask the town planning and 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 Coos County?
Yes. A new or changed septic system in Coos County needs a state construction approval from the New Hampshire Department of Environmental Services Subsurface Systems Bureau. ParcelSheet shows the USDA soil survey's septic rating at the lot, from survey area NH607 (Coos County Area, New Hampshire).
What can I build on 5 acres in Coos County?
Zoning in Coos County is set by each town and city, not the county (such as Berlin). The zoning district decides the uses, how many homes and the smallest lot it allows on 5 acres. ParcelSheet shows the lot size as mapped and the use code on the parcel record; the town planning and zoning office has the district and its rules. See the Coos County website.
What are the residential setbacks in Coos County (2026)?
Setbacks in Coos County come from the zoning code of the municipality the lot sits in: the front, side and rear distances depend on the lot's district. ParcelSheet does not draw setback lines or give a number it did not read; the town planning and zoning office gives them for the district. See the Coos County website.
Next to Coos County: Carroll County, Grafton County.
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