Does corned beef need to be covered with water in a slow cooker?

 Yes, when cooking corned beef in a slow cooker, it is recommended to cover the beef with water. This is because slow cookers use a low heat setting over a long period of time to cook the meat, and the water helps to ensure that the meat stays moist and tender. It also helps to infuse the meat with flavor from any seasonings or vegetables that are added to the slow cooker. The general rule of thumb is to use enough water to completely cover the meat, and then add any additional ingredients on top.