Preheat Oven To 325 Degrees F (165 Degrees C). Place Chicken Legs In A 9X13 Inch Baking Dish. In A Medium Bowl, Mix Together The Water, Ketchup And Vinegar . Season With Salt And Pepper To Taste, And Pour Mixture Over Chicken. Turn Chicken Pieces To Ensure That All Are Well Coated. Warm In Preheated Oven For About 25 Minutes, Or Until Heated Through.