Chemistry is a branch of physical science that studies the composition, structure, properties and change of matter.
Daily water consumption varies quite a bit. Season of the year, workload, reproductive status, diet, and climate factor into the volume of water needed by a particular horse on a specific day. As a starting point, the average horse drinks between 5 and 10 gallons (19 and 38 liters) of water each day. The horse may need slightly less if it is grazing lush pasture because fresh grass contains a high percentage of liquid.
Dehydration occurs if a horse loses too much water from its body and does not replenish it, or if a horse just is not consuming enough water every day to meet its bodily needs. A 3 to 4 percent loss of body water will cause mild dehydration. Some horses will only drink five to six gallons of water per day, will eat normally and remain healthy. These horses are the exception; their kidneys have the ability to concentrate urine and recycle more of the water back into the body.