Cover, and cook on Low for 10 to 12 hours, or on High for 4 to 5 hours. When done, remove bay leaf, and shred meat with a fork.
Place roast in slow cooker, and pour salad dressing mixture over the meat.
Combine water with salt, ground black pepper, oregano, basil, onion salt, parsley, garlic powder, bay leaf, and salad dressing mix in a saucepan. Stir well, and bring to a boil.