The Drinkwell ® Big Dog Fountain uses the same innovative watering system as the Original Pet Fountain, featuring the patented free-falling stream of water that consumers have come to rely on. A charcoal filter removes bad tastes and odours leaving your pet with fresh tasting, filtered water. Designed by a veterinarian specifically for large dogs, the Drinkwell Big Dog Pet Fountain has a separate reservoir which holds 8.5 litres of water.