Wash lemons and peel off all the zest using a vegetable peeler. Set peeled lemons aside. Add the lemon zest to a bowl and cover with sugar. Toss to combine. Cover and let sit for a minimum of 2 hours, or up to overnight.
Bring water to a boil in a pot over high heat; turn off heat and pour in the lemon-sugar mixture. Stir and let sit until the sugar is completely dissolved, about 5 minutes.
Pour through a mesh strainer back into the same bowl and discard the zest. Let cool to room temperature, 20 to 30 minutes.
Cut the lemons in half and squeeze into the bowl. Pour lemonade into a serving pitcher. Wrap in plastic wrap and chill thoroughly before serving over ice, at least 2 hours.