What is the minimum size of the water supply inlet for a flushometer tank?

The minimum size of the water supply inlet for a flushometer tank is typically 1/2 inch. This size is important for several reasons. First, a 1/2 inch inlet allows sufficient water flow to refill the tank quickly, which is vital for maintaining the performance and efficiency of the flushometer. Insufficient water supply can lead to inadequate flushing power and may cause frequent maintenance issues.

Additionally, using the appropriate size ensures that the plumbing system can handle the demand created by the flushometer, especially in high-traffic restroom environments where multiple flushes may occur in quick succession. If the inlet were smaller, like 3/8 inch or 5/8 inch, it could restrict water flow, leading to problems with pressure and insufficient flushing capabilities. A 1-inch inlet might also be too large for typical residential or light commercial applications, leading to unnecessary water usage or increased installation costs. Thus, the 1/2 inch size strikes an effective balance between performance and practicality.