Bathroom Design: Small, Not Cramped

Every ADU bathroom fights the same battle: full function in minimal feet. The classic 5×8 (40 SF) three-fixture bath wins that battle when planned well — here's how.

The layout that works. Door at one end; vanity, then toilet, then tub/shower across the far end. One wet wall (there's Module 4's rule again), everything reachable, no wasted inch. At 5×8: a 30–36" vanity, standard toilet with its required 30" width of clearance, and a 60" tub or shower. This plan has served millions of apartments because it simply works.

Upgrade moves worth their inches (when you have them):

• 6×9 or so buys a real 36" shower plus a linen cabinet — the comfort version.
• Curbless walk-in shower — barely costs more during new construction, looks modern, and quietly delivers aging-in-place readiness (lesson 8.10). Choose it by default.
• Pocket door — swings steal usable space in small baths; pockets give it back.

Shower vs. tub: rentals and most adults: a good 36"+ shower beats a tub. Include a tub only when small children are in the unit's future — or when your market data says families are the target tenant.

The unglamorous essentials that make or break it: a properly sized exhaust fan ducted outdoors and used (moisture is a small building's slow death); comfortable lighting at the mirror (a bare ceiling bulb makes every face look tired — sconces or a lit mirror fix it); an outlet near the vanity (code requires it; daily life demands it); and niches, not shelves, in the shower.

One planning note for 2BR units: a second bathroom (even a tiny 3-fixture or a half bath) changes rentability more than almost any other 25–35 SF you can spend. If the plan can absorb it, it usually should (Module 4's 1,000 SF pattern).