Spray the inside of the Crock-Pot with nonstick cooking spray.
Place the frozen meatballs into the Crock-Pot. Pour the marinara sauce and water over the meatballs. Sprinkle with garlic powder, oregano, salt, and pepper.
Cover the Crock-Pot and set to cook on low for 6 hours. When the time is done, mix in the mozzarella and Parmesan and stir to combine.
Garnish with fresh basil. Serve hot over cooked pasta or with a side of bread.