Preheat oven to 350 degrees F (175 degrees Celsius). Grease a 9x9 inch baking pan.
In a large mixing bowl, beat together margarine and sugars; add eggs one at a time, and beat until mixture is light and fluffy. Stir in peanut butter, vanilla, and water.
In a separate mixing bowl, mix together flours with salt, baking powder, and baking soda. Stir into peanut butter mixture and blend well. Spread batter into the prepared pan.
Bake in preheated oven for 30 to 35 minutes, or until the top springs back when touched. Cool and cut into 16 squares.
