The diameter of the valve for the hose needed to operate the Rainey Outdoor Shower is a 3/4” standard garden hose.
The flow rate is dependent on the PSI of the water source, which in and of itself has numerous variables: house size, distance from the water source, hose length and diameter, how "on" the water source is, etc. Normal ranges for a water source are between 40 and 80 PSI. While it would be impossible to assign an exact flow rate to the outdoor shower due to these variables, the shower flow is full, even, and steady in a typical residential setting.