Wash the strawberries and hull them. Chop about 1/2 pound of the strawberries into 1/4 in. pieces and save them off to the side. These will be used later.
Add your hulled strawberries to a blender with 1 cup of the water and blend until the mixture is completely smooth.
This next step is optional. Strain the pulp and seeds through a fine strainer. If you skip this step the seeds will settle to the bottom of your drinks. Just be mindful.
Pour the strawberry base into a large pitcher or bowl. Add the sweetened condensed milk, 4 cups of whole milk, and 3 cups of remaining water, stirring until fully incorporated.
At this point you can test the flavor. If you want to add sugar or vanilla now would be a good time. If not, then you are finished!
Finally, stir in the remainder of the strawberries that you chopped from the first step.
For best results, chill in the fridge for about 30 minutes. Then serve over ice.
