Here’s the minimum code requirements for a residential bathroom:
• Every dwelling must have a water closet (toilet), lavatory (sink), and bathtub or shower (IRC R306.1).
• Bathrooms and toilet rooms must have a minimum ceiling height of 6-feet 8-inches (IRC R305.1).
• The ceiling height above bathroom fixtures must enough for the fixture to be used for its intended purpose [IRC R305.1(2)].
• A shower or tub equipped with a showerhead shall have a minimum ceiling height of 6-feet 8-inches above an area that is 30-inches square [IRC R305.1(2)].
• There are no minimum dimensional or area requirements for a bathroom, but there are clearance requirements for individual fixtures that dictate minimum size of room according to layout of fixtures.
• A toilet requires 21-inches of clear space in front of it, and 15-inches each way of its centerline to a sidewall or adjacent fixture (IRC Figure R307.1).
• There must be 21-inches of clear space in front of a bathroom sink (IRC Figure R307.1).
• Plumbing fixtures, except toilets, must have an approved strainer at drain (IRC P2702.1).
• Hot water faucet handle must be on the left as you face the spigot (IRC P2722.2), except for single-handle mixing valves.
• Control valves at showers and tub/shower combinations must be single-handle thermostatic or pressure-balance mixing type (IRC 2708.4).
• A shower must be minimum 30-inches square, with 24-inches clearance in front of shower opening (IRC Figure R307.1).
• Minimum 21-inches clearance in front of bathtub (IRC Figure R307.1).
• Shower wall surfaces shall be finished with a nonabsorbent material to a height of at least 6-feet above floor (IRC R307.2).

• A bathroom sink, shower or bathtub must be provided with hot and cold water (IRC R306.4).
• Bathroom plumbing fixtures must be connected to a sanitary sewer or approved private sewage disposal system (IRC 306.3).
• Minimum one receptacle within three feet of each sink on an adjacent wall, or inside or on the face of the sink cabinet not more than 12 inches below countertop [NEC 210.52(D)].
• Bathroom must have a switched lighting outlet (permanently installed light fixture) [NEC 210.70(A)(1)].
• Overcurrent devices (electrical panels) are not allowed to be located in a bathroom [NEC 240.24(E)].
• Fuel-fired (gas) water heaters are not allowed in a bathroom unless installed in a sealed enclosure so that combustion air will not be taken from the living space or it is direct-vent type.
• Minimum clear opening for at least one bathroom door for new homes is now 29-inches, which means it must be at least a 30-inch door (IRC R320.2.1).
• Bathrooms must have a window with minimum 3 square feet of glazing, and window ventilation provided by a minimum openable area of 1.5 square feet, OR artifical light and a switched exhaust fan that is rated at a minimum of 50 cfm (cubic feet per minute), or a continuous fan that produces 20 cfm or more (IRC R303.3, M1507.4).  
• A bathroom is not considered habitable space, so a supply register (vent) for heating or air conditioning is not required by code (IRC R303.10).

    These requirements are based on the International Residential Code (IRC), and similar National Electrical Code (NEC) standards. Other codes and local jurisdiction amendments may be different. Also see Frequently Asked Questions (FAQ) about Minimum Code Requirements

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Here’s links to a collection of our blog posts about BUILDING CODES:

• What are the minimum code requirements for a residential kitchen?

• What are the minimum code requirements for a residential garage? 

• What are the minimum code requirements for a residential hallway? 

• When did the first Florida Building Code (FBC) begin and become effective?

• The home inspector says I have construction defects. How did my home pass inspection by the building department? 

• What is the difference between prescriptive and performance building codes?

• Can a local building department choose to not enforce selected parts of the Florida Building Code? 

• Is the latest edition of the National Electrical Code (NEC) the standard used for the electrical system of new homes?

• Why is the National Electrical Code (NEC) so hard to understand and complicated? 

• What is the purpose of the Existing Building Edition of the Florida Building Code?

• What is the most important sentence to know in the entire National Electrical Code (NEC)? 

• How often does the National Electrical Code (NEC) change?

• Does a home inspector look for code violations?