Water Closet Flush Valve Sizing

Size flush valve supply pipes for water closets (toilets) based on pressure and flow requirements.

1=tank-type (1.6 GPF), 2=flushometer (1.6 GPF), 3=flushometer (3.5 GPF).
Length of supply pipe from branch to fixture.
feet
Static pressure at branch.
PSI

Results

Required Flow-GPM
Min Pressure Required-PSI
Supply Pipe Size-inches
References: Based on ASPE fixture flow rates and flush valve manufacturer requirements