Place pork roast in a 4- to 5-quart slow cooker. Add water; sprinkle evenly with cooking sauce and pepper to taste. Cover and cook on high one hour and then on low 6 to 8 hours. Remove roast from slow cooker; shred meat and pull from the bone with a fork. Place meat on buns; top withbarbecue sauce and a scoop of coleslaw, if desired.