Make the simple syrup by combining 1 cup of water and ¾ cup of granulated sugar in a small saucepan. Heat over medium, stirring occasionally, until the sugar fully dissolves, about 2-3 minutes. Remove from heat and let it cool.

Squeeze lemons to get 1 cup of fresh lemon juice. Strain the juice to remove any seeds and pulp.

In a large pitcher, stir together the cooled simple syrup, lemon juice, and 5 cups of cold water. Taste and adjust the mixture with additional water or lemon juice as needed.