Seismic Design Category D (SDC D) per ASCE 7-22 reflects high seismic hazard — it triggers the most demanding structural requirements in the IBC/IRC seismic provisions. The Wasatch Fault is capable of magnitude 7.0–7.5 earthquakes with Peak Ground Accelerations of 0.3–0.5g in the SLC valley. SDC D requires: engineered shear wall design per SDPWS 2021 (not prescriptive tables); hold-down hardware at each shear wall end; specific structural connection requirements throughout; and a Special Inspection Program per IBC Chapter 17 for critical structural elements. SDC D is not bureaucratic — it is the structural code’s quantitative response to a documented, historically active fault system that runs beneath the communities built along the Wasatch Front.