While distilled water is not good for drinking water on a regular basis, though it can be used in a pinch, it is what should be used with powdered formulas. I know that few people feed formula to their ferrets, but this is for those who do, and for those who might formula feed other animals. Powdered formulas (Esbilac, KMR, Fox Valley formulas, Zoologic Milk Matrix formulas, etc.) should be mixed with distilled water in order to retain the balance of nutrients. Using other types of water, such as regular or bottled drinking water, changes the nutrients in the formula. Katharine Florida [Posted in FML 6555]