if only it were that easy. some of these bottled waters are toxic too and no systems in place to test for all these potential poisons. in fact, many bottled waters don't have as rigorous of standards as town treated water in US. tastes not to say all town waters are safe either because some pump with fluoride and most dont test for all possible harmful chemicals. been down this rabbit hole and even as a civil engineer it's unclear best water options.

I'd think a modified distillation. boil but don't capture initial vapor as this could trap and include chemicals lighter than pure h2o steam. but many suggest water with no nutrients extracts nutrients from your body and isn't good. so adding nutrients to distilled water may be best