The bill aims to address the ongoing shortage of low-rise residential buildings in Washington by establishing a performance-based building code compliance pathway. This new framework is intended to reduce regulatory friction, improve permitting predictability, and support off-site manufacturing and industrialized construction. The legislature recognizes that current compliance pathways are largely prescriptive and project-specific, which limits innovation and scalability in housing production. By allowing compliance to be demonstrated through measured performance rather than prescribed methods, the bill seeks to enable the reuse of approved designs across jurisdictions and streamline energy code compliance while maintaining health, safety, and welfare protections.

To implement this performance-based compliance pathway, the bill mandates the state building code council to adopt a mandatory appendix to the international building code specifically for low-rise residential buildings, defined as those with one to six stories. The council is required to convene a technical advisory group to recommend performance-based code amendments, which will include experts from various state agencies and institutions. The advisory group will develop performance criteria and ensure that the new compliance pathway aligns with existing energy codes and greenhouse gas emissions regulations. Additionally, the bill allows for the recognition of housing systems and plan certifications from independent third-party organizations as a means of demonstrating compliance with the state building code, thereby facilitating a more efficient permit review process.