How Clearly Filtered Filters WorkClearly Filtered is a bit different from one of its main competitors, ZeroWater, whose filters I'm also testing. A Landlord-Friendly Undersink SolutionBut the filtration system that I find most useful at home is Clearly Filtered's three-stage under-sink system. A goodly percentage of under-sink water filter systems require some level of installation, space for a separate tap, or even integration with a faucet. All I had to do was shut off my cold water line, unscrew the water line at the valve, and attach the water lines to the appropriate connections on the Clearly Filtered system. Anyway, none of the Clearly Filtered systems are at the bottom of the market, price-wise.