Bathroom Fixture Clearances — The 15/21/24-Inch Rules
Bathroom layouts are governed by three small numbers — 15, 21, and 24 — measured from fixture centerlines and faces. They are the difference between a legal powder room and a drawing that will not pass plan review.
Worth knowing
- The 15 in. is to centerline, not to the toilet edge — a 30 in. alcove is the practical minimum, and comfort-height elongated bowls make tight alcoves feel smaller still.
- ADA/accessibility dimensions (60 in. turning, 16–18 in. toilet centerline off the side wall) apply to covered public facilities, not private homes — do not mix the two rule sets.
- Pocket doors solve the majority of small-bath front-clearance conflicts with in-swinging doors.
- The bath fan must terminate outdoors — not in the attic. Attic-dumped fans are a mold generator and an inspection failure (M1501).
Common questions
What does the code say about toilet side clearance for Bathroom Clearances?
15 in. minimum from the water closet centerline to any wall, partition, vanity or other fixture — 30 in. total between fixtures set center-to-center. (IRC R307.1, Fig. R307.1)
What does the code say about front clearance for Bathroom Clearances?
21 in. minimum clear space in front of the water closet, lavatory and bidet. (IRC R307.1)
What does the code say about shower access for Bathroom Clearances?
24 in. minimum clearance in front of the shower opening. (IRC R307.1)
Adopted edition by state
Base-code year from BuildSpec’s adoption records. States often amend the base code, and your city or county may differ, so confirm with your building department.
Related sections and guides
This guide is BuildSpec’s own summary, not code text. It cites the 2021 International Residential Code and the 2023 National Electrical Code as model standards. The IRC 2021 text itself is in the Code Library for signed-in members; BuildSpec publishes no NEC text, which is at nfpa.org.Neither is an adoption record: your state may be on a different edition with amendments — check your jurisdiction page or get an Address Report.