Surprisingly, no. You don't need to add water to the roast and spices in the slow cooker. This cut of pork is naturally juicy, and yes, fatty. In just a few minutes it will juice up in the pot. At the end of the cooking time, you should have a decent 1/2 to 1 cup of drippings. You can use these to moisten the meat, make soup or chili, or discard.