Place water, ham bone, onion, and garlic in a large pot. Simmer 1 1/2 hours - 2 hours or until tender. Add potato, carrots, and celery. Simmer 30 min. longer. Remove ham bone. Cut up meat and return to soup. Thicken with four blended with a little cold water. Add milk and heat gently. Season to taste with salt and pepper. Makes 10 to 12 servings.