Livestock Water Needs Calculator
Estimate daily and weekly water for cattle, dairy cows, horses, sheep, goats, pigs, and hens, plus trough refills, how long a tank lasts, and the hot-weather increase.
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Best for farms sizing troughs, tanks, hauled water, and well capacity for livestock. Updated .
Animals drinking
Presets are gallons per head per day in moderate weather from extension tables. Pick the closest class; lactating animals drink far more than dry ones.
Weather and equipment
Water needed
Gallons per day = Σ head × gallons per head for that class. Hot weather multiplies by (1 + increase %). Refills = gallons ÷ trough size; tank days = tank ÷ gallons per day. Planning figures: feed moisture, salt, milk yield, and humidity all change intake, and animals must never run out, so size for the hot-weather number.
About the livestock water needs calculator
Water is the nutrient animals need most and the one farms plan least. This calculator adds up daily water for the animals you have, using extension requirement tables by species and class, then turns the total into weekly and monthly gallons, trough refills per day for your tub size, how many days a storage tank or hauled load lasts, and a hot-weather figure. Use it to size a stock tank, decide whether a well or hauling schedule keeps up in July, or plan a new pasture's water.
Lactating animals drink far more than dry ones and heat raises intake by half or more, so pick the closest class for each group and size for the hot-weather number.
Where the gallons come from
The presets are gallons per head per day in moderate weather (about 70 F) from North Dakota State University Extension's livestock water tables: a 900 lb pregnant beef cow about 9.7 gal, a 900 lb lactating cow 16.9 gal, 600 lb growing cattle 7.8, 1,000 lb finishing cattle and a 1,600 lb bull 12.6. Dairy cows giving 50 lb of milk need 23 to 27 gal and 30 to 36 at 80 lb; a dry cow 9 to 13. A mature idle 1,100 lb horse drinks 8.2 gal at 68 F and a lactating mare 13.5. Pregnant ewes need 1 to 2 gal and lactating ewes 2 to 3; grower pigs 0.5 to 2, finishing pigs 2 to 3, pregnant sows 3 to 6, and lactating sows 5 to 8. Where a table gives a range the preset is the midpoint.
Goats are not in the NDSU tables; Oklahoma State's meat goat handbook gives three-quarters to one and a half gallons for a mature goat, so the preset is 1.1, and the lactating doe figure of 2.5 is borrowed from lactating ewes and labeled a planning figure. Laying hens use Penn State's minimum of 5 gallons per 100 birds a day, 0.05 gal per hen.
Heat, troughs, and tanks
NDSU's tables show what heat does: the same idle horse goes from 8.2 gal at 68 F to 12.7 gal at 86 F, and 600 lb cattle from 7.8 gal at 70 F to 12.7 at 90 F, increases of 55 to 63%. The hot-weather setting multiplies the total by an editable increase, 50% by default, and the tank card shows how many days your storage lasts at both settings. Refills per day is simply gallons divided by trough size; a number above 2 or 3 usually means the trough is too small or needs a float valve. Animals should never run out, so size troughs, tanks, and pump capacity for the hot-weather figure, not the average.
Worked example: a small mixed farm in summer
Ten lactating beef cows at 16.9 gal (169 gal), two mature horses at 8.2 gal (16.4 gal), six dry goats at 1.1 gal (6.6 gal), and 25 laying hens at 0.05 gal (1.25 gal) need 193.3 gal a day in moderate weather for 43 animals, about 1,353 gal a week and 5,878 gal a month. That is 1.9 refills a day of a 100 gal trough, and a 1,500 gal tank lasts 7.8 days. Switch to hot weather at a 50% increase and the farm needs 289.9 gal a day, 2,029 gal a week, 2.9 trough refills, and the same tank lasts only 5.2 days.
Sources
- North Dakota State University Extension, Livestock water requirements (AS1763, revised 2026). Tables of gallons per head per day for beef cattle by weight and temperature, dairy cattle by milk yield, horses by class and temperature, sheep, and swine, with water intake rising with temperature. Accessed Sep 4, 2026.
- Penn State Extension, Management requirements for laying flocks. Provide at least 5 gallons of water per 100 laying hens daily, and never let hens go without water for more than 12 hours. Accessed Sep 4, 2026.
This calculator gives planning estimates from the numbers you enter. It is not accounting, tax, veterinary, or legal advice. Replace the defaults with your own farm records whenever you have them.
Frequently asked questions
How much water does a cow drink per day?
A dry or pregnant beef cow drinks roughly 7 to 10 gallons a day in mild weather and a lactating cow 12 to 17 or more; at 90 F both climb toward 20 gallons. Dairy cows in milk need 20 to 40 gallons depending on production. Plan on 20 gallons per cow-calf pair in summer to be safe.
How much water does a horse drink a day?
About 8 gallons for a mature idle horse in moderate weather, 11 to 13 gallons in heat or with moderate work, and up to 20 or more for hard work in hot weather. Lactating mares need about 13 to 14 gallons.
How much water do goats and sheep need?
Roughly 1 to 2 gallons a day for a dry ewe or mature goat and 2 to 3 gallons when lactating, more in heat. Small ruminants are sensitive to dirty water, so a smaller trough that is cleaned often beats a big one that is not.
How big a water tank do I need for my livestock?
Multiply your hot-weather daily gallons by the number of days you need to bridge between fills or pump runs, then add a margin. For 290 gallons a day, a 1,500 gallon tank gives about five days; a 3,000 gallon tank about ten. Check that your pump or hauling rate can refill it in time.
Does this account for water in feed or snow?
No. Animals on lush pasture or silage drink less than these table figures, and cattle eating snow in winter can partly replace drinking water, but neither should be relied on. The figures are for planning supply, and your veterinarian or extension office can advise on specific rations and climates.
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