In a large bowl, combine the flour, sugar, cocoa, baking soda and salt. In another bowl, whisk the eggs, sour cream, water, milk, oil and vanilla. Stir into dry ingredients just until moistened. Fold in chocolate chips.
Fill greased or paper-lined muffin cups two-thirds full. Bake at 325° for 20-25 minutes or until a toothpick comes out clean. Cool for 5 minutes before removing from pans to wire racks.