Countertop water filter systems are often overlooked by those looking for a high quality drinking water filtration system. There are several advantages to countertop water filters; 1) portability and ease of installation 2) Easy servicing; 3) no long runs of tubing that can get contaminated. Big Brand Water Filter countertop drinking water filtration systems accept industry standard 2 1/2" by 9 7/8" water purification cartridges and are available in single, double and triple configuration.