Water Supply Fixture units and minimum fixture pipe sizes 

Water Supply Fixture units and minimum fixture pipe sizes for copper pipe. 

Individual Fixtures

Min
pipe size

Private
Home

Bar sink

½”

1.5

Bathtub or bath/shower

½”

4.0

Clothes washer

½”

4.0

Dishwasher

½”

1.5

Hose Bib

½”

2.5

Hose Bib, each additional

½”

1.0

Kitchen Sink

½”

1.5

Laundry Sink

½”

2.0

Lavatory (bathroom sink)

½”

1.0

Shower

½”

2.0

Toilet gravity tank 1.6

½”

2.5

Toilet gravity tank 3.5 >

½”

3.0

Whirlpool bath

½”

4.0

  Pressure range, 40 to 60 PSI, at a developed distance of 80 feet for copper pipe.  

Meter and street service
(ends at the meter)

Building supply and branches
(begins at the meter)

Fixture units
(from chart above)
80 feet

200 ft 300 ft 400 ft 500 ft 600 ft

Ύ”

½”

6

3 2 1 1 1

Ύ”

Ύ”

19

11 8 6 5 4

Ύ”

36

23 19 17 14 12

Ύ”

1-1/4”

39

39 32 27 25 22

1-1/4”

76

44 36 30 27 24

1-1/2”

85

85 67 55 49 41

A standard one-bath home with kitchen sink, dishwasher, water heater, clothes-washer, 1.6 tank toilet, lavatory, tub/shower combo and two hose bibs would be counted as 18 fixture units.  

Most standard two bath homes   consisting of kitchen sink, dishwasher, water heater, clothes-washer, two 1.6 tank toilet, two lavatories, one shower, one tub/shower combo, and two hose bibs would be counted as 23.5 fixture units.  

Most standard three bath homes   consisting of kitchen sink, dishwasher, water heater, clothes-washer, three 1.6 tank toilet, four lavatories, two showers, one tub/shower combo, one whirlpool bath and two hose bibs would be counted as 34 fixture units.    

"  1" CPVC will have about the same opening as 3//4" copper, the 3/4 will be the equivalent of 1/2" copper, and forget about 1/2" CPVC for anything other than a single fixture, (and keep its length as short as possible), since its bore is miniscule."  hj

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