Plumbing Pipe Sizes


The following pipe sizes are the minimum required pipe size for single fixtures and are subject varying code regulations. When other fixtures are added to the same pipe, the size may increase.





Drainage sizes

FixturespacerSize in InchesspacerSize in Millimeters
Bathtubspacer1.5spacer38
Beer cabinetspacer1.5spacer38
Bidetspacer1.25spacer32
Clothes washerspacer2spacer50
Dishwasherspacer1.5spacer38
Floor drainspacer2spacer50
Laundry tubspacer1.5spacer38
Lavatory - single or double(bathroom sink)spacer1.25spacer32
Shower 1 headspacer1.5spacer38
shower 2-3 headsspacer2spacer50
Kitchen Sink - single or doublespacer1.5spacer38
Toilet / water closetspacer3spacer76

Water supply pipe sizes

FixturespacerSize in InchesspacerSize in Millimeters
Bathtubspacer.5spacer15
clothes washerspacer.5spacer15
Dishwasherspacer1/2spacer15
Hose bibbspacer1/2spacer15
Lavatoryspacer3/8spacer10
Kitchen sinkspacer1/2spacer15
Shower headspacer1/2spacer15
Water closet (tank type)spacer3/8spacer10