Preheat the oven to 350 degrees F (175 degrees C).

Remove and discard giblets. Rinse turkey and pat dry. Place turkey upside-down (with breast facing down) in a roasting pan.

Place 1/2 of the butter in the cavity of the turkey. Cut remaining butter into pieces and rub over the outside of the skin. Pour water into the pan and cover with foil.

Cook in the preheated oven until the internal temperature of the thighs has reached 180 degrees F (80 degrees C), 3 to 3 1/2 hours.