What is the minimum shower size allowed by code?
A shower must have at least 900 square inches of interior area and be no less than 30 inches in any dimension, maintained up to 70 inches above the drain (IRC P2708.1).
The IRC sets a minimum shower compartment of 900 square inches (0.58 m²) of interior cross-sectional area, with no interior dimension less than 30 inches (762 mm). A 30-by-30-inch stall just meets the minimum area.
The required area and 30-inch dimension are measured at the finished interior surfaces — not counting valves, the showerhead, soap dishes, and grab bars — and must be held all the way up to 70 inches (1778 mm) above the drain.
These are minimums; a larger stall improves comfort and accessibility.
Need this scoped to your jurisdiction?
Adopted edition and local amendments vary by city and county. Ask Donnie checks your jurisdiction and cites the exact adopted section.
Ask Donnie →General information based on the International Residential Code (a model code). This is AI assistance to verify — not legal advice. Confirm the adopted edition and any local amendments with your local building department (AHJ) and a licensed professional before you build.