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, ground 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 to combine.
5. Bring the mixture to a boil, then reduce the heat to low. Simmer for 45 minutes to 1 hour, stirring occasionally.
6. Serve hot, garnished with your favorite toppings.