Grease 12x8-inch (2-quart) baking dish. In greased baking dish, combine uncooked spaghetti, water and spaghetti sauce; mix well. Add meatballs; turn to coat with sauce. (Cover spaghetti completely with sauce.) Cover tightly with foil; refrigerate at least 8 hours or overnight.
Heat oven to 350°F. Bake covered for 45 minutes. Uncover; sprinkle with cheese. Bake uncovered for an additional 5 to 10 minutes or until casserole is bubbly and cheese is melted. Sprinkle with parsley.
