Chop the onion and celery. Mince the garlic cloves. Peel and slice the carrots.

Place the onion, carrot, celery, garlic, chicken, broth, water, and wild rice in the slow cooker and cook on low for 8 hours or high for 4.

In a medium bowl, stir together the milk and the flour. Slowly add this mixture to the slow cooker, stirring to combine. Coninue to cook for an additional 30 minutes to 1 hour to thicken. Season with salt and pepper and serve.