California IDEX Practice Exam 2025 - Free IDEX Practice Questions and Study Guide

The correct choice focuses on the occupancy group of the building, which is essential in determining the minimum number of toilet fixtures required. Different occupancy groups have specific plumbing requirements based on their intended use and the expected number of occupants. For example, a restaurant will have different fixture requirements compared to a warehouse, reflecting the nature of activities and the number of people typically present.

Occupant load is a significant factor; however, the occupancy group provides the necessary context to apply the relevant codes and standards that dictate the appropriate number of fixtures. This ensures compliance with health, safety, and accessibility standards, contributing to a functional and safe environment for all users.

In contrast, while building size might influence certain design decisions, it does not directly determine restroom fixture requirements as per code. Similarly, time of day does not affect the number of fixtures required nor does distance from the main entrance impact the computation for required plumbing fixtures in terms of occupancy compliance.