Distilled water is the purest form of water. Water distiller is the only way that gives distilled water. Countertop water distillers purify the water by 99.7%. Home water distiller purifies the water in 3 steps. In first step, water is boiled. Then, in second step, it is passed through a charcoal. In third step, it is purified again that removes rest of the impurities and gives you purified water.