In a pitcher, combine the sugar and hot water. Stir until the sugar is completely dissolved.
Add the freshly squeezed lemon juice.
Pour in the cold water and stir well.
Refrigerate until chilled.
Serve over ice and garnish with lemon slices if desired.
Notes
Optional Add-InsTry adding one of these for a fun twist: Fresh mint leaves Sliced strawberries Fresh raspberries Blueberries Cucumber slices Peach slices A splash of sparkling water