Slice the limes into quarters.

Blend the limes with 4 cups of water for one minute.

Place a fine mesh sieve over a large bowl and slowly pour the lime mixture through it.

Press the leftover pulp in the sieve with a rubber spatula to extract the excess juice.

Rinse out the blender.

Add the trained lime juice back to the clean blender with the remaining water, sugar, and sweetened condensed milk. Blend on low for 1 minute.

Skim the foam off the top.

Pour over ice when serving with a lime wedge.