Horses and Water

A full size horse (e.g. 500kg or 1100 pounds) drinks about 30 liters (6 gallons USA or 5 gallons UK/Canada) per day. However this amount can vary by 50% or more depending on:

  • Food. Horses eating dry food (e.g. hay, dry grass) will need to drink more, while horses fed on moist food such as grass or soaked mash will drink less. In the case or green grass which is wet with dew or rain, a horse may drink very little as it gets most of its water needs from its food.
  • Weather. During hot weather, especially if the horse is standing in the sun, it will require additional water to compensate for the water lost through sweating.
  • Exercise and Work. A horse that is being worked or exercised with require additional water, especially if it is sweating. Even if the horse is not visibly sweating, it may be doing so under the saddle or saddle rug.
  • Size. Water consumption, like food consumption, tends to be proportional to size.
  • Health. Certain medical conditions, such as Cushings or Diabetes, can increase the amount of water a drinks. A few medical conditions, such as colic, can reduce the amount of water a horse drinks. Consequently, it can useful to track the amount of water your horse drinks (e.g. with a water meter) as an early indication of illness.
  • Water Temperature. Horses tend to drink less if the water is cold, especially during winter. After all, a horse which is cold from being out in cold weather all day, does not want to drink a lot of freezing water which will make if even colder. In some cases, the reduction in water consumption can make the horse more prone to certain illnesses (e.g. impaction colic). One of the advantages of heaters (e.g. heated drinkers, buckets) is that horses will drink more.
  • Pregnant or Nursing. A mare which is nursing or heavily pregnant will need more to drink, as she is drinking for her baby as well as herself.
  • Individuals. Just like people vary in the amount they drink, so do horses. One can put two horses of identical size and health in neighboring boxes, feeding them exactly the same, yet one may well drink substantially more than others.

Due to all these variables, the actual amount of water a horse requires on any given day can be much more or much less than the theoretical average. The best advice is to make sure that your horse has regular access to water, that it is heating above freezing in winter, and that one tries to observe any unexpected change in the amount a horse is drinking.

Safe Water

Horse buckets, drinkers and troughs should be cleaned on a regular basis. In particular, rotting or fermenting food should be removed promptly and the water replaced, since polluted water can result in horse illnesses.

If the pastures have streams or ponds, these should be fenced off if the water is not clean, to avoid potential illnesses. Even if the water is clean, any unsafe access points (e.g. steep or slippery slopes) should be fenced off to protect the horses from injury.

If the water is heated, any electrical cables and connections should be protected to avoid horses chewing on them or damaging them, for the protection of both equipment and horse. If electrical cables are subject to wear or movement, they should be inspected periodically to ensure that they are are still safe and functional, in particular that there is no risk of short-circuiting.

Access

Horses should normally have free access to water at all times, especially if they are eating dry food (such as hay) or during hot weather. 

One exception to this is that after heavy exercise or work they should not be allowed to drink too much water until they cool down, as suddenly drinking large amounts of water on a hot stomach can result in colic. Another exception is that if a horse has been deprived of water during winter temperatures (e.g. if their drinker or water bucket has frozen), they should not be allowed to drink a large quantity of cold water at once as drinking lots of cold water quickly. In both cases one should provide only a moderate amount of water, then wait half an hour before providing more water.

To prevent horses being deprived from water during freezing temperatures, one should protect water pipes. It their drinkers are prone to freezing, one should  use a heated water bucket or heated drinker.