Place 1 cup of sugar and 1 cup of water in a small saucepan. Bring to a boil and simmer until the sugar is dissolved. Set the syrup aside to cool.
In a large pitcher combine the syrup, lemon juice, and 5 cups of cold water. Taste and add more water (or ice), if desired. Refrigerate until ready to serve.
Place sugar, lemon juice, and 1 cup of water in a blender. Process briefly until the sugar is dissolved (the mixture will be bubbly/foamy for a few minutes afterwards). Pour this mixture into a pitcher along with the remaining 5 cups of water, stir until combined. Taste and add more water (or ice), if desired. Refrigerate until ready to serve.
