Distilled water goes through an interesting process to remove any and all particulates. Reverse osmosis filtered water instead utilizes a membrane to filter out the impurities. I cannot remember where I read it, or why it was, but Reverse Osmosis filtered water is EXTREMELY superior to distilled water for grower purposes and can be found for the same price. In fact, most water machines in front of grocery stores provide RO filtered water for $0.25 to $0.35 per gallon.
Spring water will contain some material. Most of the time it is with reason. Crystal Geyser, Alhambra, and Arrowhead are all fine for growing with.
The void of anything in distilled water makes it great for precipitating a pure aluminum phosphate in chemistry class but a poor solution for growing with. For the same cost RO water is a much better option.
Fuck... I really need to get the scientific, botanical, reasoning for this. I see a lot of people using distilled and I always rec against it but cannot ever site why. Enh... Something to do today now, I suppose.