Boulder County Building Code Amendments

Building Code Update – Effective July 1, 2026

The Boulder County Building Code Amendments are adopted by the Board of County Commissioners. The Board has approved updated building codes and amendments that will take effect on July 1, 2026. Beginning on that date, all new building projects will be reviewed under the 2021 International Codes (I-Codes) along with Boulder County’s local amendments.

• Boulder County Building Code Approved Amendments, July 1, 2026

Boulder County’s local amendments include additional requirements for energy efficiency, sustainability, and ignition-resistant construction. These updates are designed to better protect the community and prepare for the impacts of a changing climate. They also align Boulder County with anticipated statewide standards for wildfire resilience.

Adopting the 2021 I-Codes also improves Boulder County’s Building Code Effectiveness Grading Schedule (BCEGS) rating. A stronger BCEGS score benefits the community by demonstrating to the insurance industry that Boulder County uses up-to-date building codes and maintains strong code enforcement.

The updated code applies to all Building Permit Applications for properties in unincorporated Boulder County submitted on or after July 1, 2026. Cities and towns within Boulder County adopt and enforce their own building codes independently.

Boulder County Building Code

The following publications shall hereby be adopted as the Boulder County Building Code by reference, with deletions and amendments as indicated:

1. 2021 International Building Code (the “IBC”), including specifically Appendix Chapters C, E, H, I, J, and K;
2. 2021 International Residential Code (the “IRC”), including specifically Appendix Chapters AE, AF, AH, AJ, AM, AO, AQ, AR, AS, AT, AU, and AX; and Appendix RD.
3. 2021 International Existing Building Code (the “IEBC”), including specifically Appendix Chapter Appendix B;
4. 2021 International Mechanical Code (the “IMC”);
5. 2021 International Plumbing Code (the “IPC”);
6. 2021 International Gas Code (the “IFGC”);
7. Current Version Adopted by the Colorado State Electrical Board of the National Electric Code (the “NEC”);
8. 2021 International Energy Conservation Code (the “IECC”), including appendixes CB, CD, RB, and RD;
9. 2021 International Green Construction Code (the “IgCC”) including Normative Appendixes A, B, C, and D; and Informative Appendixes E, F, G, H, I, J, K, L, M, and N;
10. 2021 International Code Council Performance Code (the “ICCPC”);
11. 2021 International Swimming Pool and Spa Code (the “ISPSC”); and
12. 2023 Colorado Model Electric Ready and Solar Ready Code.

All International Codes as published by the International Code Council (ICC), 4051 West Flossmoor Road, Country Club Hills, IL 60478-5795; and the NEC, as published by the National Fire Protection Association, One Batterymarch Park, Quincy, MA 02169-7471; with additions, deletions and amendments as per the Boulder County Building Code Amendments.

Past Building Codes

• For building permits applied for from March 31, 2025 – June 30, 2026: Building Code Amendments, March 31, 2025 through June 30, 2026
• For building permits applied for from June 6, 2022 – March 30, 2025: Building Code Amendments in effect June 6, 2022 through March 30, 2025
• For building permits applied for from 2017 – June 5, 2022: Building Code Amendments in effect Jan. 1 2017 through June 5, 2022
• For building permits applied for in 2016: Past 2015 Building Code Amendments
• For building permits applied for from Jan. 1, 2013 – Dec. 31, 2015: 2012 Boulder County Building Code Amendments
• For building permits applied for from Jan. 1, 2011 – Dec. 31, 2013: 2009 Boulder County Building Code Amendments

Previous versions of the Boulder County Building Code Amendments are available as reference for all building permits issued prior to the current amendments. Please contact Building Safety and Inspection Services for a copy of older Amendments.