I don't have anything for her if she won't drink water that's not distilled.
Not getting any minerals in your water, abs drinking 2 gallons a day, especially if she's on the lower end of the human scale (meaning she's not a big dude and women tend to be smaller than men, on average), drinking 2 gallons a day of any water might be too much for her system to balance if she's not getting enough salt and other electrolytes.