Shape ground beef into 6 oval patties and place them in a single layer in the slow cooker.
In a bowl, whisk together cream of mushroom soup, brown gravy mix, and water until smooth.
Pour the soup mixture evenly over the patties, ensuring they are fully coated.
Cover and cook on LOW for 5–6 hours or HIGH for 2½–3 hours, until patties reach 160°F internally.
Serve hot with gravy over mashed potatoes, egg noodles, or rice.
Notes
For thicker gravy, remove the lid during the last 30 minutes of cooking or stir in a cornstarch slurry. Ensure beef reaches 160°F internal temperature.