Floor drains must be constructed with a minimum diameter of:

The minimum diameter for floor drains is set at 2 inches to ensure adequate drainage capacity and to prevent clogs. This size allows for sufficient flow of water and the easy passage of debris that may enter the drain, reducing the risk of blockages. Additionally, a 2-inch diameter is typically compatible with the most common plumbing systems and fixtures, providing a balance between efficiency and manageability. Drains with smaller diameters may not handle water flow effectively, especially during heavy use, which could lead to overflows or drainage issues. Therefore, the regulation specifies a minimum of 2 inches to maintain optimal function and safety standards in plumbing systems.