21 Apr 2026 3 min read

How are local building codes developed?

Local building codes in the United States are not created from scratch by most cities or counties. Instead, they are primarily developed through a two-part system: model codes produced nationally (or internationally) and then adopted and customized at the state, county, or municipal level. This decentralized approach allows codes to address broad safety standards while accommodating local conditions like climate, seismic risks, geography, or economic factors. There is no single national building code (except for manufactured housing).

1. Development of Model Building Codes

The foundation comes from model codes, which are consensus-based documents created by organizations like the International Code Council (ICC). The ICC produces the widely used "I-Codes," including:

International Building Code (IBC) for commercial structures
International Residential Code (IRC) for homes
International Energy Conservation Code (IECC), plumbing, mechanical, fire, and existing building codes

How model codes are developed and updated:

The process is open and occurs on a three-year cycle.
Anyone (individuals, industry groups, government officials, architects, engineers, builders, or the public) can submit code change proposals with supporting rationale, data, or cost analyses.
Proposals go through multiple stages: public comment periods, technical committee hearings (where experts review merits, safety impacts, and feasibility), and voting.
Final decisions are made through a governmental consensus process, where voting members (primarily code officials representing the public interest) approve or reject changes. This helps minimize undue influence from any single interest group.
The ICC incorporates input from standards organizations (e.g., for materials or testing) and aims for minimum requirements focused on health, safety, structural integrity, fire protection, accessibility, energy efficiency, and affordability.
New editions are published (e.g., 2021, 2024, or upcoming 2027 versions), with errata and updates as needed.

Other organizations, such as the NFPA (for certain fire codes), contribute, but the ICC family dominates in most jurisdictions.

2. Adoption and Customization into Local Building Codes

Model codes have no legal force until a government body adopts them (by reference or with modifications) through legislation or ordinance. Adoption typically happens at one of these levels:

State level: Many states adopt a statewide building code (often based on the latest ICC editions, sometimes with state-specific amendments). The state legislature or a designated board/commission handles this. Some states mandate that local jurisdictions follow the state code (with limited or no amendments allowed); others set it as a minimum.
Local level (county, city, or village): In states without a strong statewide code—or where locals are empowered to act—cities and counties adopt their own versions. This is done via city council or county commission ordinance.

Typical local adoption process:

A building department, technical review committee, or appointed board reviews the current model code (or the state's version).
They evaluate local needs (e.g., high wind zones, cold climates, or urban density) and propose amendments—often making requirements stricter for safety or loosening in limited cases where justified.
Stakeholder input is gathered from builders, architects, engineers, contractors, developers, community groups, and the public through hearings, comment periods, or workshops.
The proposed code (or amendments) is presented to the legislative body (e.g., city council).
Public notice is required (often 15+ days in advance), followed by hearings for further input.
The governing body votes to adopt the code as law, usually by ordinance. It may be adopted "by reference" (pointing to the full model code text) plus local amendments.
Once adopted, there is often a delayed effective date to allow training for builders, inspectors, and officials.

Local amendments must generally follow state rules (e.g., in some places, they can only be more stringent and must cite specific local climatic, topographic, or geological conditions). After adoption, the code becomes enforceable law, with penalties for noncompliance.

3. Enforcement and Ongoing Maintenance

Enforcement is handled by local building departments (or state agencies in some cases) through plan reviews, building permits, and inspections at various construction stages.
Codes are periodically updated when a new model edition is released or when local conditions change. Updates follow a similar review-and-adoption process.
Training and education for industry professionals often occur before new requirements take effect.

Variations and Examples

The exact process varies by jurisdiction because building regulation is primarily a state and local power. Some states update frequently and require locals to conform; others leave it entirely to cities/counties.

In most states:

The state legislature adopts and updates a statewide building code based on ICC models (including IBC, IRC, IECC, and IEBC).
Local jurisdictions (counties, cities, villages) may adopt their own building or construction code if it "conforms generally" with the state code. They can also add amendments for proper administration and enforcement.
If a local area does not adopt a conforming code within two years of a state update, the state building code applies by default (with some exceptions, like farm construction).
The city maintains its own local building code and amendments through its Planning Department/Permits and Inspections division, tailoring the state framework as allowed.

This system evolved historically from early local fire-safety rules (dating back to the 1600s–1800s) to today's model-code framework, which promotes consistency while allowing flexibility.

Key benefits: Leverages national expertise and data for safety without every small town reinventing the wheel.
Challenges: Variations can create complexity for builders working across borders, and update cycles sometimes lag.