1. In a large pot, brown the ground beef over medium heat. Drain off any excess fat.
2. Add the chopped onion, celery, and green bell pepper to the pot. Cook until the vegetables are tender.
3. Stir in the chili seasoning mix, cumin, garlic powder, salt, and black pepper. Cook for another minute.
4. Add the kidney beans, pinto beans, tomato sauce, diced tomatoes, and water. Stir well to combine.
5. Bring the mixture to a boil, then reduce the heat and let it simmer for about 45 minutes, stirring occasionally.
6. Taste and adjust seasoning if needed. Serve hot.