We always use distilled water in our soap because it is pure. The soap making process works best with water that is soft and does not contain excess minerals.
Goats milk has been used for centuries as a skin moisturizer because of its high cream/fat content. It contains lactic acid which will exfoliate the skin, and is high in vitamin A, which nourishes and helps with healing. Goats milk is hypoallergenic.
Buttermilk hydrates the skin, since it is high in fats and oils that penetrate the skins surface. When added to soap, buttermilk creates a natural skin cleanser that is safe for use on sensitive skin types.