Clean the ham hocks thoroughly. Place the water and ham hocks in a large Dutch oven or kettle. Simmer for 45 minutes. Wash and sort the peas. Place in a large bowl. Cover with warm water. Soak for 45 minutes. Pour the water off of the peas. Add the peas, onion, celery and pepper to the ham hocks. Boil on medium heat for 2 hours, or until the meat and peas are tender. Stir occasionally. Remove the ham hocks. Cut the meat from the bones. Discard bone. Return the meat to the soup. Combine a small amount of evaporated milk and flour to make a paste. Stir in the remaining milk gradually. Stir until well blended. Add to the soup. Cook and stir until the mixture comes to a boil and thickened. Makes 8 servings