Melt 2 sticks of butter in large skillet and add onion and celery. Sauté until onion is transparent, then add sausage.
Break up sausage and stir frequently. Add in the rice and continue to saute until the sausage and rice are browned. Additional butter may be added, if necessary.
In large mixing bowl, add stuffing mix. Combine ingredients from skillet into bowl; add salt and pepper. Slowly pour chicken stock and water while mixing until completely moistened. More water may be added, if necessary.
Place in a large baking pan. Cover with foil and bake for one hour.