In a blender, combine 6 cups of cold water, 5 lime wedges, and 1/2 cup of granulated sugar. Blend on high for 30-45 seconds until smooth.

Strain the mixture through a fine mesh strainer into a large bowl to catch pulp and lime skin.

Return the strained liquid to the blender and add 1/4 cup of sweetened condensed milk. Blend on high for 30 seconds until well combined and frothy.

Serve over ice in tall glasses, garnishing with lime slices or mint.