In a 4-quart Dutch oven cook onion and celery in hot oil over medium heat for 5 minutes, stirring occasionally. Add garlic; cook and stir for 30 seconds. Add broth and water. Bring to boiling. Add potatoes, beans, and squash. Return to boiling; reduce heat. Cover and simmer for 10 to 12 minutes or until vegetables are tender.
Stir in turkey, tomato, thyme, sage, and pepper. Heat through. Ladle soup into bowls.