Notes
This drink varies greatly with the drinker's preferences. You can make it with or without ice. I make it without ice, but with chilled water so the drink starts out at a cool temperature.
The ratio of Scotch to water can vary wildly. If you're trying to open up a barrel proof, or some other closed Scotch, sometimes just a dash or two of water will suffice. If you prefer the Scotch to be more diluted, it is not unheard of to go all the way to a 4 to 1 water to Scotch ratio.
Use high quality spring or filtered water.