Hudson, NH Zoning Regulations & Building Permits
Official references and local checks
Use the official references below to identify the rules that apply to your address, then confirm parcel-specific requirements with the local authority before filing an application.
Official references
- Population:
- 25,965
- County:
- Hillsborough County
- State building code:
- NH State Building Code (based on 2018 IBC)(statewide default)
- State ADU law:
- Yes — New Hampshire RSA 674:71-73 (enacted by SB 146, signed March 2016) requires municipalities that adopt zoning to allow at least one accessory dwelling unit as a matter of right or by conditional use permit/special exception in all zoning districts that permit single-family dwellings. HB 1291 (2024), which would have expanded this to two ADUs by right, passed the House but was killed in the Senate.
- FEMA flood map:
- Search flood zones
- Planning department:
- Hudson Planning Board
Before you apply
- Call the Hudson Planning Board: (603) 886-6000
- Check FEMA flood zone for your parcel — flood-zone status changes setbacks, foundation requirements, and insurance.
- Check your HOA CC&Rs and recorded deed restrictions — they are common in Hudson and frequently restrict ADUs, fences, and exterior changes beyond what zoning allows.
Key Zoning Facts
Hudson is a town in Hillsborough County, New Hampshire, with a population of approximately 25,965 (2020 Census). Located along the Merrimack River near the Massachusetts border, Hudson manages land use and development through its zoning ordinance, administered by the Hudson Planning Board.
Hudson's zoning ordinance divides the town into several districts, including two residential zones, two business zones, and an industrial zone. The R-1 district requires 40,000 sq ft minimum lots, while the R-2 (General Residential) district requires 20,000 sq ft.
Key Zoning Districts
Hudson's primary residential zoning districts include:
- R-1 (Residential) — Minimum 40,000 sq ft lots with 35 ft front, 20 ft side, and 25 ft rear setbacks. Maximum height of 35 ft.
- R-2 (General Residential) — Minimum 20,000 sq ft lots with 30 ft front, 15 ft side, and 20 ft rear setbacks. Maximum height of 35 ft.
Other districts include:
- B (Business) — General business district for retail, office, and service uses
- B-2 (Highway Business) — Highway-oriented commercial district for larger-scale retail and services
- I (Industrial) — Manufacturing, warehousing, and related industrial uses
ADU Regulations (Accessory Dwelling Units)
New Hampshire state law (RSA 674:72-73) requires all municipalities to allow ADUs (Accessory Dwelling Units) as a matter of right on any property with a single-family dwelling. Hudson must comply with this state mandate. Key points:
- One ADU is permitted per single-family lot
- The ADU may be attached to or detached from the primary dwelling (subject to local standards)
- Municipalities cannot prohibit ADUs but may adopt reasonable regulations regarding size, parking, and other dimensional standards
- Contact the Hudson Planning Board for the town's specific ADU application requirements and any local dimensional standards
Building Code
Hudson follows the NH State Building Code (RSA 155-A), which is based on the International Building Code (IBC) and International Residential Code (IRC). All construction must comply with the state building code.
Development Process
Development in Hudson generally requires obtaining the appropriate permits from the town's planning and building departments. The process typically involves:
- Zoning Verification — Confirm that your proposed use is permitted in the applicable zoning district
- Site Plan Review — For commercial, multi-family, and certain other projects, submit a site plan to the Planning Board
- Building Permit — Apply for a building permit with construction documents
- Inspections — Schedule required inspections during construction
- Certificate of Occupancy — Obtain final approval before occupying the structure
For projects that do not conform to existing zoning, property owners may need to seek a variance or special exception from the Hudson Zoning Board of Adjustment (ZBA).
Key Considerations
Before starting any development project in Hudson, property owners should:
- Verify the zoning classification of their property
- Review setback, height, and lot coverage requirements for the applicable district
- Check for any overlay districts or special regulations
- Determine if the property is in a flood zone using FEMA's flood map service
- Confirm whether HOA covenants or deed restrictions apply
- Contact the Hudson Planning Board at (603) 886-6000 for pre-application guidance
Disclaimer: This guide provides general information about zoning in Hudson, NH and should not be relied upon as legal advice. Zoning codes are subject to change. Always verify current regulations with the Hudson Planning Board before making development decisions.
Regulatory Layers That Apply in Hudson
Your property is subject to ALL of these regulatory layers. Each one can impose additional requirements beyond the others.
Federal
- FEMA flood mapping: check parcel-specific flood-zone status
- View FEMA Flood Map
State — New Hampshire
- Building Code: NH State Building Code (RSA 155-A)
- State ADU Override: Yes (NH RSA 674:72-73 requires municipalities to allow ADUs)
County — Hillsborough County
City / Municipal
The municipality's zoning ordinance, building-code enforcement, and local permits form the primary local layer of land-use regulation for your property.
Overlay Districts
No overlay districts identified.
Private Restrictions
- Private covenants, deed restrictions, condominium rules, or association rules can impose requirements beyond zoning.
- Check HOA CC&Rs and deed restrictions for additional requirements.
Statewide Context (New Hampshire)
Local data for Hudson is limited. The following state-level facts apply across New Hampshire and are inherited by this page until city-specific details are verified.
- State Building Code
- NH State Building Code (based on 2018 IBC)
- State ADU Preemption
- Yes — state law overrides local rules
- Coastal Zone
- Yes
- Wildfire Zones
- No
ADU Rules in Hudson
State law (statewide context, not city-specific):
New Hampshire RSA 674:71-73 (enacted by SB 146, signed March 2016) requires municipalities that adopt zoning to allow at least one accessory dwelling unit as a matter of right or by conditional use permit/special exception in all zoning districts that permit single-family dwellings. HB 1291 (2024), which would have expanded this to two ADUs by right, passed the House but was killed in the Senate.
For local size, setback, and parking specifics, contact the Hudson Planning Board.
Permit Costs & Timelines
Check Current Permit Fees & Timelines
Permit fees and review times can vary by project type, scope, valuation, and required approvals. Check the current schedule with the local permitting authority before filing.
Check current Hudson permit information →Official Sources
City-specific