Make the simple syrup: To a medium-sized saucepan placed over medium heat, add 1 cup water, ½ cup honey and slices from 4 ripe peaches. Stir well, bring mixture to a simmer, and cook for 10 minutes.
Pour mixture through a fine mesh strainer set over a large heat-safe bowl to remove any peach skin and pulp from the simple syrup.
Mix 1 cup fresh lemon juice, 4 cups cold water and peach simple syrup in a pitcher and serve over ice.
Notes
If fresh peaches aren't available, this recipe can be made with frozen peach slices.