The filtration principle of the water purifier is to filter impurities or bacteria through the membrane through the tap water pressure. At present, ultrafiltration machine and pure water machine are mostly used in general families, and the standard filtration stage is 5. Under normal circumstances, after being filtered by the water purifier, the water can basically reach the standard of pure water, and the water does not contain any impurities. This kind of water is best to quench your thirst. Drinking more water is not good for your health.