In a bowl, combine the butter, eggs and vanilla. Combine the dry ingredients; add to the butter mixture and mix well. Stir in water and chocolate chips until combined. Pour into a greased 13-in. x 9-in. x 2-in. baking pan. Bake at 350° for 30-35 minutes or until brownies pull away from the sides of the pan. Cool on a wire rack. In a saucepan, combine the chips, milk and butter until chips and butter are melted. Remove from the heat; whisk in the confectioners' sugar and vanilla until smooth. Cover and refrigerate until frosting is room temperature, about 20 minutes; frost brownies. Cut into bars.