Common drinking water filters: a reverse osmosis water filtration system, under sink (point of use), countertop, and inline filters. The most effective drinking water filters are usually placed in a cabinet beneath the sink where water lines are directed to dedicated drinking water faucets located on sink surfaces. The most common drinking water problems are: dirt / sediment, chlorine, lead, cysts and generally poor tasting water. To solve a water problem for your entire home you may want to check out a whole house water filter. Check out our water filter housing replacement o-rings.