ORIGINAL: OldScaleGuy
I believe it would depend on the condition of your tap water. Too hard, too much lime, too much iron, too soft, etc. I have used distilled water for the ''cleaner'' water it provides and it is very inexpensive.
I've manufactured paint in different states. Tap water is all that I have ever used.
Michigan ground water can smell and have a yellow tint. We still ran it into the vats straight from the tap.
Floetrol, by it's nature, would increase drying time.
Other conditions, such as temperature and humidity, can effect drying times, too.