In a large bowl, cream together the peanut butter, butter, and white sugar until smooth. Stir in the water and vanilla. Combine the flour and salt; stir into the peanut butter mixture. Drop by rounded spoonfuls onto an ungreased cookie sheet. Press down lightly using the tines of a fork.
Bake for 10 to 15 minutes in the preheated oven. Let cookies cool completely before removing from baking sheets.
