Bore water can be used to fill swimming pools; however, please note that this water is untreated ground water. It is very dependent on the quality of your bore water as to whether its suitable to use in a pool. Natural minerals and salts are present in ground water which may stain areas it has contact with it.
More chemicals need to be used when using bore water in your pool. It is highly advisable to get a comprehensive water analysis once your bore is drilled.