Clean your preparation area and rinse ginger root under cool running water. Slice off any dried-out pieces from the ginger root.
In a saucepan, simmer 20 ounces of water with the ginger root and sugar for approximately 10 minutes. Remove from heat to begin to cool.
In a pitcher place the cooling ginger water, and add in the remaining 20 ounces of room temperature water and lemon juice. Add in extra ginger slices for garnish.
Place in the refrigerator for at least 2 hours or until cold.
Serve over ice. Add ginger or lemons for garnish as desired.