Understanding Horses’ Water Requirements

Water is one of the essential nutrients a horse’s body needs to carry out various vital functions. Here’s what to remember about supplying your horse with water.

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Understanding Horses
Especially with the hot summer weather prevalent in much of the country, it’s important to ensure horses have access to water at all times. | Photo: iStock

Water is one of the essential nutrients a horse needs to perform a number of life-support functions, including digestion and thermoregulation. Especially with the hot summer weather prevalent in much of the country, it’s important to ensure horses have access to water at all times.

As horse owners, we know it’s important to provide free-choice water to horses at all times, but it is also imperative that the water is of good quality, clean, and palatable.

A number of circumstances can lead a water deficiency in horses, including unpalatable taste, lack of water offered, or loss of thirst due to exertion. The effects of insufficient water intake include decreased performance, decreased feed intake, dehydration, and eventually, if not remedied, death.

On average, a typical 1,100-pound horse at maintenance consumes four to nine gallons of water per day. The amount of water a horse requires can vary depending upon several factors:

The type, amount, and quality of feed consumed

  • Fresh pasture contains between 60-80% moisture and provide a large amount of the horse’s water requirements when grazing.
  • Hay and grain are very low in moisture, causing horses to drink more water to meet their needs.
  • Higher levels of protein and sodium in the diet also increase the horse’s water requirement as urinary volume increases.

Temperature and humidity

  • Ambient temperatures above 85°F will increase a horse’s drinking frequency and volume.
  • Colder temperatures (below 45°F) can reduce a horse’s water consumption

Health status

  • Horses with excessive water losses from diarrhea require more water per day.

Physiological stage

  • Type of physical activity performed can affect the amount of water a horse needs.
  • Performance horses should be allowed to drink water prior to and during prolonged activity. Horses should be cooled down adequately prior to being allowed to drink free-choice after exercise..
  • Lactating mares require between 50-80% more water per day for milk production compared to horses at maintenance.

With temperatures soaring in many parts of the country, it’s important to remember how crucial water is to keeping horses healthy. Always ensure your horses have access to fresh, clean water at an appropriate temperature, and ensure they’re drinking the fluids provided. Consider adding a few ounces of salt or an electrolyte supplements to horses’ diets if lack of water consumption is a concern.


Written by:

Kristen M. Janicki, a lifelong horsewoman, was born and raised in the suburbs of Chicago. She received her Bachelor of Science degree in Animal Sciences from the University of Illinois at Urbana-Champaign and later attended graduate school at the University of Kentucky, studying under Dr. Laurie Lawrence in the area of Equine Nutrition. Kristen has been a performance horse nutritionist for an industry feed manufacturer for more than a decade. Her job entails evaluating and improving the performance of the sport horse through proper nutrition.

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