I just know what it takes to get enough snow melted down to fill up one gallon jug.
It takes a good bit, though usually around winter time there is enough for her to collect and melt down to save several gallons.
As I said though finding the room to store all of this water until Spring time when it is needed is the hardest part. Gallons and gallons of water take a good bit of space, but she lucked out because she has a basement that she never uses execpt for storing the melted snow.
Though for anyone who does have extra space, to do something like this is going to save money, create healthier plants, and help the planet at the same time.