First, place the spaghetti and 1/2 cup water in the slow cooker.
Next, take sausage out of the casings, roll into small meatballs (see video), and place in the slow cooker. Pour all but 1/3 of marinara in the slow cooker.
Now, cover and cook 6 hours on low.
Finally, pour rest of the marinara in and mix everything together. You can add parm and basil if desire but great just as is.