Revised May 2017

G1801, How to Size a Farm and Home Water System

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How to Size a Farm and Home Water System

Bob Broz
Extension Water Quality State Specialist
Division of Food Systems and Bioengineering

A farmstead water system should be able to supply the peak flow rate continuously for two hours. A home water system should be able to supply peak demand continuously for one hour. If the peak use rate exceeds the maximum well yield, provide intermediate storage.

If you want water for fire control, the system should be able to supply 20 gallons per minute at 60 pounds per square inch pressure.

For more details on computing system capacity, see the Private Water Systems Handbook by Midwest Plan Service, available online from Iowa State University at or at::

  • Agricultural Plan Service
    200 Agricultural Engineering Building, MU
    Columbia, Mo. 65211.

Home flow rates

Table 1 gives water use rates of several commonly used items. For an easy way to determine flow rates for a home, refer to Table 2. Add the home flow rate to the farmstead rate to determine total system capacity.

Table 1
Home and outdoor living water requirements

Use Flow rate Total gallons used
Adult or child   50 to 100 per day
Baby   100 per day
Automatic washer 5 gallons per minute 30 to 50 per load
Non-automatic washer 5 gallons per minute 15 to 45 per load
Dishwasher 2 gallons per minute 7 to 15 per load
Garbage disposer 3 gallons per minute 4 to 6 per day
Kitchen sink1 3 gallons per minute 2 to 4 per use
Shower or tub1 5 gallons per minute 25 to 60 per use
Toilet flush2 3 gallons per minute 4 to 7 per use
Bathroom lavatory 2 gallons per minute 1 to 2 per use
Water softener regeneration3 5 gallons per minute 50 to 100 per time
Backwash filters3 10 gallons per minute 100 to 200 per backwashing
Outside hose faucet 5 gallons per minute  
Fire protection4 10 gallons per minute 1,200 per 2 hour period
1Water flow restricting valves and shower heads can reduce flow and water use by up to 50 percent.
2Ordinary toilet; low flow toilets will reduce water usage by 40 to 90 percent.
3Water hardness, softener size, etc. affect water use.
4For limited fire fighting; at least 10 gallons per minute with a 1/4-inch nozzle at 30 psi for 2 hours per day (1,200 gallons). Preferred: 20 galllons per minute at 60 psi for 2 hours per day (2,400 gallons).

Table 2
Recommended flow rates for home water systems

Number of bedrooms Number of bathrooms in home
1 1-1/2 2 3
Gallons per minute flow rate
2 6 8 10  
3 8 10 12  
4 10 12 14 16
5   13 15 17
6     16 18

Table 3 gives farm water requirements. Use this information to determine peak use in gallons per day, then refer to Table 4 to read directly flow rate in gallons per minute.

Table 3
Approximate farm water requirements

Water use per animal Gallons per day
Milk cow 35 to 45
Dry cow 20 to 30
Calves (1 to 1-1/2 gallons per 100 pounds body weight 6 to 10


  • Finishing
  • Nursery
  • Sow and litter
  • Gestating sow


3 to 5

Beef animal 8 to 12
Sheep 2
Horse 12
100 chicken layers 9
100 turkeys 15
Water use for milk houses and parlors
Washing operation Water volume

Bulk tank

  • Automatic
  • Manual


50 to 60 gallons per wash
30 to 40 gallons per wash

in parlor (volume increases for long lines in a large stanchion barn)
75 to 125 gallons per wash
Pail milkers 30 to 40 gallons per wash
Miscellaneous equipment 30 gallons per day

Cow preparation

  • Automatic
  • Estimated average
  • Manual

(gal per wash per cow)

1 to 4-1/2
1/4 to 1/2

Parlor floor 40 to 75 gallons per day
Milk house floor 10 to 20 gallons per day
Water use flow rates
Air temperature, size of animal, species, age, milk or egg production, type of ration, dry matter consumed and other variables affect livestock water consumption. Average summer values are listed — use 60 percent for cool weather. Also use 60 percent of the tabulated livestock consumption for pond storage if the average year-round temperature is about 50 degrees Fahrenheit.
  Minimum gallons per minute Preferred gallons per minute
Automatic waterers
cattle, hogs or sheep (20 to 40 head per bowl)
poultry (100 to 150 layers)
Cleaning hose for milk house and dairy utensils 3 5
Cleaning and manure removal hose for milking barn or hog house 5 10
Outdoor hydrant for uses other than firefighting 3 5

Table 4
Flow rates for livestock production

Peak use Flow rate
Up to 1,000 gallons per day (minimum) 8 gallons per minute
1,500 gallons per day 12 gallons per minute
2,000 gallons per day 16 gallons per minute
2,500 gallons per day 20 gallons per minute
3,000 gallons per day 24 gallons per minute
4,000 gallons per day 28 gallons per minute
5,000 gallons per day 32 gallons per minute
6,000 gallons per day 36 gallons per minute
7,000 gallons per day 39 gallons per minute
8,000 gallons per day 42 gallons per minute
9,000 gallons per day 45 gallons per minute
10,000 gallons per day 48 gallons per minute
12,000 gallons per day 50 gallons per minute
Original author
Fred M. Crawford

G1801 How to Size a Farm and Home Water System | University of Missouri Extension