Blend the Base: Gather your blender and add 6 cups of cold, filtered water, 5 whole limes cut into wedges, and 1/2 cup of granulated sugar. Blend on high for about 30 seconds until smooth.

Strain the Mixture: Prepare a fine mesh strainer or cheesecloth over a bowl and pour the blended mixture into it, extracting as much liquid as possible while keeping the pulp and skin contained.

Add Creaminess: Rinse the blender, return the strained liquid to it, and pour in 1/4 cup of sweetened condensed milk. Blend for about 20-30 seconds until smooth and frothy.

Serve and Enjoy: Fill your glasses with ice, pour the creamy lime mixture over, and garnish with a lime slice if desired.