Distillation is a process that boils water. The steam from the boiling water is then recondensed into water. Since the water is boiling, this will kill any micro-organism. This is a very high quality water, however, it is deoxygenated and volatiles can get through in this process. The maintenance of these systems can be a challenge and they use energy to operate. Lastly, these systems are usually countertop models. Most people do not want anything else on the kitchen counter tops.