A.O. Smith AO-US-200 Under-Sink Water Filtration System

The A.O. Smith AO-US-200 is a 2-stage under-sink water filtration system designed to complement A.O. Smith water heaters as part of a comprehensive household water quality solution. Stage 1 provides coarse filtration of sediment and particulates. Stage 2 is a proprietary A.O. Smith carbon composite filter block certified under NSF/ANSI 42 (taste, odor, chlorine), NSF/ANSI 53 (lead, cysts, turbidity), and NSF/ANSI 401 (emerging contaminants including pharmaceuticals, pesticides, and PFAS compounds). Triple NSF certification on a single cartridge makes the AO-US-200 one of the most comprehensively certified 2-stage under-sink systems in the residential market. Filter life is 600 gallons (approximately 6 months for 2-3 person household drinking use). A dedicated brushed nickel dispensing faucet is included. Replacement filters (AO Smith part DS-102) are available through A.O. Smith water product dealers and online.