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

UseFlow rateTotal gallons used
Adult or child 50 to 100 per day
Baby 100 per day
Automatic washer5 gallons per minute30 to 50 per load
Non-automatic washer5 gallons per minute15 to 45 per load
Dishwasher2 gallons per minute7 to 15 per load
Garbage disposer3 gallons per minute4 to 6 per day
Kitchen sink13 gallons per minute2 to 4 per use
Shower or tub15 gallons per minute25 to 60 per use
Toilet flush23 gallons per minute4 to 7 per use
Bathroom lavatory2 gallons per minute1 to 2 per use
Water softener regeneration35 gallons per minute50 to 100 per time
Backwash filters310 gallons per minute100 to 200 per backwashing
Outside hose faucet5 gallons per minute 
Fire protection410 gallons per minute1,200 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 bedroomsNumber of bathrooms in home
Gallons per minute flow rate
5 131517
6  1618

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 animalGallons per day
Milk cow35 to 45
Dry cow20 to 30
Calves (1 to 1-1/2 gallons per 100 pounds body weight6 to 10


  • Finishing
  • Nursery
  • Sow and litter
  • Gestating sow


3 to 5

Beef animal8 to 12
100 chicken layers9
100 turkeys15
Water use for milk houses and parlors
Washing operationWater 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 milkers30 to 40 gallons per wash
Miscellaneous equipment30 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 floor40 to 75 gallons per day
Milk house floor10 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 minutePreferred 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 utensils35
Cleaning and manure removal hose for milking barn or hog house510
Outdoor hydrant for uses other than firefighting35

Table 4
Flow rates for livestock production

Peak useFlow rate
Up to 1,000 gallons per day(minimum) 8 gallons per minute
1,500 gallons per day12 gallons per minute
2,000 gallons per day16 gallons per minute
2,500 gallons per day20 gallons per minute
3,000 gallons per day24 gallons per minute
4,000 gallons per day28 gallons per minute
5,000 gallons per day32 gallons per minute
6,000 gallons per day36 gallons per minute
7,000 gallons per day39 gallons per minute
8,000 gallons per day42 gallons per minute
9,000 gallons per day45 gallons per minute
10,000 gallons per day48 gallons per minute
12,000 gallons per day50 gallons per minute
Original author
Fred M. Crawford