Place the frozen meatballs in the crockpot. You can use homemade or store-bought frozen meatballs, depending on your preference.
In a separate bowl, combine the crushed tomatoes, tomato sauce, water, Italian seasoning, garlic powder, onion powder, salt, and pepper. Mix well until all the ingredients are thoroughly combined.
Pour the sauce mixture over the meatballs in the crockpot, ensuring that all the meatballs are covered evenly.
Set the crockpot to the low heat setting and cook the meatballs for 4 to 6 hours. Cooking times may vary depending on the size and brand of the meatballs, so it's essential to check for doneness.
After the initial cooking time, check the meatballs for tenderness. If they are not fully cooked, continue cooking for an additional hour or until they reach the desired texture.
Once the meatballs are fully cooked, you can serve them directly from the crockpot or transfer them to a serving dish. If desired, garnish with grated Parmesan cheese and fresh basil for added flavor and presentation.
Serve the slow cooker frozen meatballs as an appetizer with toothpicks or as a main dish alongside pasta, rice, or bread.