Place a piece of foil, about 30 inches long, into the bottom of a 9x13 inch roasting pan. Place the roast on the foil in the pan.
In a separate small bowl, combine the mushroom soup with the onion soup mix. Mix well and pour over the roast. Sprinkle with the water. Fold foil over and seal all edges.
Bake at 300 degrees F (150 degrees C) for 4 hours.
