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Zoning Guide

Londonderry, NH Zoning Regulations & Building Permits

Data-only stub — facts unverified locally. Confirm with the planning department before relying on details.
Last updated: Verified:

What we have on file vs. what to verify locally

We don't have editor-verified zoning prose for Londonderryyet. Here's the structured data we do have, and the highest-leverage steps to confirm specifics for your parcel.

What we have on file

Population:
26,456
County:
Rockingham 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:
Londonderry Planning Department

Verify these locally

  • Call the Londonderry Planning Department: (603) 432-1100
  • 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 Londonderry and frequently restrict ADUs, fences, and exterior changes beyond what zoning allows.

Key Zoning Facts

Planning Department
Londonderry Planning Department(603) 432-1100
Building Code Edition
NH State Building Code (IBC/IRC based)
ADUs Allowed
Yes

Londonderry Zoning Overview

Londonderry is a town in Rockingham County, New Hampshire, with a population of approximately 26,456 (2020 Census). Located in southern New Hampshire near Manchester-Boston Regional Airport, Londonderry manages land use and development through its zoning ordinance, administered by the Londonderry Planning Department.

Londonderry's zoning ordinance divides the town into several districts, including the AR-1 (Agricultural-Residential) district requiring 2-acre minimum lots, a residential zone (R-III) with 12,000 sq ft minimums, three commercial zones, and an industrial zone.

Key Zoning Districts

Londonderry's primary residential zoning districts include:

  • AR-1 (Agricultural-Residential) — Minimum 2 acre lots with 50 ft front, 30 ft side, and 30 ft rear setbacks. Maximum height of 35 ft.
  • R-III (Residential) — Minimum 12,000 sq ft lots with 30 ft front, 12 ft side, and 20 ft rear setbacks. Maximum height of 35 ft.

Commercial and industrial districts include:

  • C-I (Commercial) — General commercial district for retail, office, and service uses
  • C-II (Commercial) — Commercial district for a range of business and professional uses
  • C-III (Highway Commercial) — 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. Londonderry 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 Londonderry Planning Department for the town's specific ADU application requirements and any local dimensional standards

Building Code

Londonderry 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 Londonderry generally requires obtaining the appropriate permits from the town's planning and building departments. The process typically involves:

  1. Zoning Verification — Confirm that your proposed use is permitted in the applicable zoning district
  2. Site Plan Review — For commercial, multi-family, and certain other projects, submit a site plan to the Planning Board
  3. Building Permit — Apply for a building permit with construction documents
  4. Inspections — Schedule required inspections during construction
  5. 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 Londonderry Zoning Board of Adjustment (ZBA).

Key Considerations

Before starting any development project in Londonderry, 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 Londonderry Planning Department at (603) 432-1100 for pre-application guidance

Disclaimer: This guide provides general information about zoning in Londonderry, NH and should not be relied upon as legal advice. Zoning codes are subject to change. Always verify current regulations with the Londonderry Planning Department before making development decisions.

Regulatory Layers That Apply in Londonderry

Your property is subject to ALL of these regulatory layers. Each one can impose additional requirements beyond the others.

Federal

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)
View New Hampshire zoning overview

County — Rockingham County

    City / Municipal

    The city's zoning ordinance, building codes, and local permits form the primary layer of land-use regulation for your property.

    Overlay Districts

    No overlay districts identified.

    Private Restrictions

    • HOA / CC&Rs common: Yes
    • Check HOA CC&Rs and deed restrictions for additional requirements.

    Statewide Context (New Hampshire)

    Local data for Londonderry 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 Londonderry

    ADUs:Allowed(statewide context — not city-specific)

    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.

    Source (New Hampshire)

    For local size, setback, and parking specifics, contact the Londonderry Planning Department.

    Permit Costs & Timelines

    Permit Costs & Timelines

    Specific permit fee schedules for Londonderry are available from the local planning department. Fees vary based on project type, scope, and valuation.

    Check Londonderry permit fees →

    Official Sources

    City-specific

    Town of Londonderrylondonderrynh.orgOfficial source