A novel water flow facilitator for granular filter devices that operate under gravity and contain granular particles, further consisting of plastic pellets that are 2 to 100 times, preferably 5 to 20 times larger than the granular particles; the plastic pellets having an aspect ratio of 0.5 to 10, preferably 1 to 4; that comprise about 1 to 50%, preferably 5 to 15% of the weight of the filter media; that have a specific gravity of 0.5 to 2, preferably 0.9 to 1.5. The plastic pellets should contain antimicrobial agents that protect the granular media from microbiological growth. The plastic pellets are made from any of the following plastics: polyolefins, various kinds of polyacrylates, polyvinyl polymers, nylon, polycarbonates etc. The plastic pellets may contain fillers such as calcium carbonate, titania, silica, or alumina. The invented flow facilitator is utilized in a gravity fed granular filter device to remove contaminants such as chlorine, taste and odor-causing compounds, solvents, pesticides, dissolved organic impurities, dissolved heavy metals and non-metallic impurities such as perchlorates. The invented flow facilitator is utilized in a gravity fed granular filter device in which the media consists of activated carbon, synthetic ion exchange resins, silica, alumina, titania, green sands, iron oxides or mixtures thereof.