The Culligan US-3UF-R filter cartridge should be replaced every 6 months to keep the system working efficiently and to keep your family safe from harmful contaminants. The Culligan US-3 Ultra Filtration Undersink Drinking Water System reduces: bacteria, viruses, reduces chlorine, taste & odor, lead, lindane, atrazine, and microbial cysts. This premium filtration system does not produce waste water like competitive reverse osmosis systems that are out on the market today. This Culligan water filtration system is set apart by including a filter life indicator, leak sensor with alarm, chrome faucet, quick connect fittings, 3-in-1 filter cartridge for easy replacement. Easy-change filters make changing filters a snap, eliminates the need to turn off your water supply.