Idaho communities adopt new square footage definitions for impact fees

Idaho Falls City Council is considering a new square footage definition for residential properties that could reshape impact fees for homeowners. This proposal, discussed during the July 7, 2025 work session, aims to clarify how square footage is calculated, particularly regarding unfinished spaces like basements and garages.

The initiative stems from a model already in use by several Idaho communities, including Sandpoint and Boise, for over 15 years. The model allows cities to charge additional impact fees as homes are expanded, addressing concerns about affordable housing in resort towns. The proposed definition emphasizes climate-controlled areas of a home, excluding unfinished basements and garages from square footage calculations. This approach reflects the unique housing dynamics in Idaho Falls, where unfinished spaces do not contribute to immediate housing impacts.

Council members engaged in a robust discussion about the implications of this definition. They noted that while unfinished basements are often required to have heating systems, they typically do not lead to increased occupancy until they are finished. This raises questions about when and how impact fees should be assessed. The advisory committee suggested that fees could be charged when a basement is converted to finished space, aligning with practices in non-residential developments.

The council is weighing the potential benefits of this new definition against the need to ensure that development impacts are accurately captured. As the city moves forward, the outcome of this discussion could significantly affect future residential development and the financial responsibilities of homeowners in Idaho Falls.