Distillation and deionization are two different processes that produce pure water. Distillation involves boiling the source water and collecting the steam, which leaves behind all impurities such as bacteria, sediment, and protozoa. On the other hand, deionization is achieved by passing the source water through a cation or anion exchange system, which removes all ions. Depending on the source water, distilled water can be more pure than deionized water – but that doesn't necessarily mean that it's better.
Deionized water is not suitable for drinking since it lacks ions that your body needs. However, it is often used for cleaning car parts like windshields, radiators, and car engines. It is also used in dentistry mouth rinsing, wound cleaning, and medical surgery since it is 100% free of impurities.
For personal use, you can find individual containers of deionized water through a retail supplier. Unless very high purity water is required, deionized water is often a better alternative because it can be made more quickly and for less money.