To make the simple syrup, combine sugar and boiling water and stir until dissolved. Allow to cool.

In a pitcher, add the cooled syrup to lemon juice and remaining water. Stir and taste. If you prefer sweeter, add a couple more tablespoons sugar. If you prefer tarter, add juice from 1/2 lemon.

Serve over ice. If desired, garnish with lemon slices, sprigs of mint, or sprigs of lavender.