Cut the fat from edges of ham slices. Add fat to a medium cast-iron skillet. Cook over medium heat until fat renders.
Score edges of ham slices. Add ham to skillet, and cook for 3 to 4 minutes on each side. When cooked, remove ham from skillet; set aside. Add water, stirring to deglaze. Cook until mixture comes to a boil and thickens slightly, about 5 minutes. Serve ham and gravy with grits and buttermilk biscuits.