Minimum Size (in inches)

Fixture Unit

Trap

Branch

Automatic clothes washer

2

2

2

Basement floor drain

3

3

3

Bath: sitz

1 1/2

1 1/2

2

Bathtub

1 1/2

1 1/2

1 1/2

Combination fixture

2

2

2

Dental cuspidor

2

2

2

Dishwasher

1 1/2

1 1/2

1 1/2

Disposal unit

1 1/2

1 1/2

1 1/2

Drinking fountain

1 1/4

1 1/4

1

Floor drain in residential laundry room

2

2

2

Floor drain in toilet room

3

3

3

Floor drain in utility room

3

3

3

Industrial floor drain

4

4

4

Kitchen sink unit

1 1/2

1 1/2

1 1/2

Laundry tray

1 1/2

1 1/2

1 1/2

Lavatories

1 1/4

1 1/4

1

Santistand

3

4

6

Shower stall

1 1/2

1 1/2

1 1/2

Sink: bar or soda fountain

1 1/2

1 1/2

1 1/2

Sink: barium

2

2

2

Sink: chemical

1 1/2

1 1/2

1 1/2

Sink: clinic

3

4

6

Sink: kitchen, residence

1 1/2

1 1/2

1 1/2

Sink: plaster

2

2

2

Sink: service

3

3

3

Sink: service wall type

2

2

2

Sink: three compartment

2

2

2

Urinal: lip

1 1/2

1 1/2

1 1/2

Urinal: pedestal

3

3

3

Urinal: stall

2

2

2

Urinal: trough

1 1/2

1 1/2

1 1/2

Water closet: Greater than 1.6 gallons per flush

3

3 or 4

6

Water closet: 1.6 gallons per flush or less

3

3 or 4

4