Pre heat oven to 350º and lightly grease three 9 inch cake pans. In a large bowl mix water and cocoa powder until smooth and let mixture cool. In another bowl sift flour, baking soda, baking powder and salt. In a separate large bowl cream together butter and sugar until light and fluffy. Beat in eggs one at a time and then add the vanilla. Alternating add in the flour mixture and then the chocolate mixture beating until all ingredients have been completely blended. Spread batter evenly into prepared pans and bake for 25-30 minutes.