What is the minimum size of a fixture water supply for a service sink?

The minimum size of a fixture water supply for a service sink is typically 1/2". This size ensures adequate water flow for the various tasks for which a service sink is used, such as utility duties, cleaning, and sometimes maintenance work. A 1/2" supply line provides a balance between adequate pressure and volume, allowing for effective operation without causing excessive strain on plumbing systems. Smaller diameters, like 1/4", may be insufficient in volume and pressure for the demands of a service sink, while larger sizes would be unnecessary and could lead to complications in fitting and installation. Therefore, the 1/2" size is both standard and practical for service sink applications, making it the most suitable choice.