Squeeze the juice from the lemons, removing the seeds.
Remove the green tops from the strawberries, place in a blender or food processor with 1 cup of water, and blend on high for 1 minute.
Strain the strawberry juice using a rubber spatula to press the liquid out.
Mix the lemon juice, strawberry juice, and remaining 5 cups of water together and add the sugar and stir until the sugar is dissolved.
Store in the refrigerator.