Horses can drink 5 to 20 gallons a day. Their need and volume depend on the amount of activity, feeding style, and the climate they live in. Each day they may take in different amounts. Maitreya has his water bucket fixed and has a drink. He approves. First, he plays with the water to rinse his mouth and clear the top debris floating in his bucket. The hissing sound is the water running through the water float and hose. Horses drink water by siphoning/sucking it up. They do not lap the water like a dog.