What is the standard dimension for a bathroom sink drain?

The standard dimension for a bathroom sink drain is 1 1/4 inches. This size is commonly used for most bathroom sinks because it effectively manages the flow of wastewater while preventing clogs. The smaller diameter also allows for a more compact drain assembly, which is suitable for the limited space often available in bathroom cabinetry.

In plumbing, maintaining the appropriate pipe sizes is crucial for both functionality and compliance with building codes. The 1 1/4-inch diameter is specifically designed for residential sink applications, providing an optimal balance between drainage capacity and the prevention of backflow or slow drainage issues.

While there may be variations in other plumbing situations, such as kitchen or laundry drains which may require larger diameters, for standard bathroom sinks, 1 1/4 inches is the most widely accepted dimension.