Mix together the barbecue sauce, ketchup, onion, celery, water, garlic, honey, brown sugar, Worcestershire sauce, chili powder, hot pepper sauce, salt, and black pepper in a slow cooker until thoroughly combined. Place the pork roast into the mixture, spoon sauce over the meat, and set the cooker to Low. Cook 7 to 8 hours; to serve, shred the meat with 2 forks, and serve with sauce.
