Combine Ham and Water (enough to cover just the bottom of the pot) in slow cooker. Cook on low for 6 hours or high for 3 hours.
After 6 hours on low or 3 hours on high, remove bone from ham (ham should be falling off of bone) and add sauerkraut. Continue to cook on low for about 4 hours. (You could add small red potatoes or diced potatoes at this time as well.).