Sift flour, baking powder, and baking soda twice. Place in a small bowl. Beat the sugar and eggs in a large mixing bowl until sugar is dissolved. Add butter and mix into egg mixture thoroughly. Add sour cream, water, vanilla extract, and beat. Add flour mixture and cocoa and beat slowly just until flour is absorbed. Do not overbeat. Fold in chocolate chips and pour into buttered Bundt pan. Bake at 180ºC for 1 hour. When cool, sift powdered sugar on top.