Kidney stones are a well known possible complication of a colectomy. You lessen the risk by properly hydrating, and not drinking excessive amounts of alcohol and caffeine. It is true that the small intestine never absorbs water as well as the colon did, but you can compensate for that by properly hydrating. In 27 years with J Pouch I never had kidney stones but my surgeon warned me about them and said if I didn’t drink a lot of fluids it could happen. He scared me straight into the proper hydration hygiene. What I do is drink a lot of herbal tea. I drink a large 16 ounce mug of it at bedtime. If you get lazy or sloppy with your hydration hygiene, you may get dehydrated and get kidney stones. As well as general malaise.