Blend the Base: Combine 6 cups cold filtered water, 5 lime wedges, and 1/2 cup of granulated sugar in a high-speed blender. Blend on high for about 30 seconds until the limes are fully pulverized.

Strain the Mixture: Place a fine mesh strainer over a bowl or pitcher and pour the blended mixture into the strainer, discarding the lime pulp and skins.

Add Creaminess: Rinse the blender, return the strained liquid, and add 1/4 cup of sweetened condensed milk. Blend until smooth and frothy.

Serve Over Ice: Fill glasses with ice and pour the creamy lemonade over. Garnish with a lime slice if desired.