Table 403.1 specifies minimum plumbing fixtures based on occupancy type and occupant load (calculated per IBC Table 1004.5). Key requirements — Assembly (A-1 theaters): WC 1 per 125 male / 1 per 65 female. Assembly (A-2 restaurants): WC 1 per 75 male / 1 per 75 female. Business (B offices): WC 1 per 25 male / 1 per 25 female, plus 1 service sink. Educational (E): WC 1 per 50 male / 1 per 50 female. Mercantile (M): WC 1 per 100 male / 1 per 100 female. Residential (R-2 apartments): 1 WC, 1 lav, 1 tub/shower, 1 kitchen sink per unit. All public-use toilet rooms must be accessible per ICC A117.1. Hot water required at lavatories in food service and healthcare. Separate facilities required when total occupant load exceeds 15. This table directly impacts building design — restroom count drives floor plan layout, plumbing risers, and construction cost.