My Riding Stables 2: A New Adventure (EP)

The hose station must be purchased at the office computer – it's under the saddle tab and costs $150. Once you've purchased it, go to the stables and install it. When a horse is in the stables, you can choose to either brush it or hose it down – when you hose it down, the grooming goes a lot quicker. Do not move the water above about midway up the horse's neck or you will lose quite a bit of the horse's trust!
 
Note that cleaning a horse with the hose will not get you a gold horseshoe ranking, as you can only earn those by manually brushing the horse.