How do water purification systems work There are not any single water purification systems that can reduce all the impurities found in today’s water supplies. This is why home water purifier systems have become more popular. They are your last chance to purify your water before using it for drinking, cooking, and showering. Home water treatment systems are divided into two broad categories. Point-of-use (POU) and point of entry (POE). The POU systems are cheaper and usually easier to maintain than POE units. POU systems are usually installed in the kitchen and bathroom. Countertop and faucet mount filters attach to the sink faucet by replacing the aerator with a simple diverter valve, aerator combination. Giving you the option of filtered or unfiltered water as you need it. These systems are easy to install and filter replacement is easy as you can stand at the counter to replace them. The only drawback to countertop filters is they take up some of your co