Thats the problem, distilled water. Distillation is expensive, inefficient and produces lots of hazardous waste. Australia is currently debating that very problem with the distillation/desalination plants they want to build. It will consume huge amounts of energy and release lots of salt and mineral laden water into the ocean.

It will never take off until they figure out a way to reliably use tap water. Even then, what do you do during a drought with water rations? Take a bath or fill up your car?