Mix flour, salt and pepper in a shallow bowl. Dredge steaks in flour mixture. Melt butter in a skillet over medium heat; add steaks and brown on both sides. Arrange steaks in a lightly greased 13"x9" baking pan; set aside. Combine soup, water and mushrooms. Pour soup mixture over steaks; cover with aluminum foil. Bake at 325 degrees for 45 to 50 minutes. Uncover; bake an additional 15 minutes.