Our son, age 10 months and a salt loser, doesn't care for juice, either. When he was diagnosed with constipation, they said to put him on any flavor juice he would drink; he wouldn't drink any, but I don't know if that was due to his teething or because he didn't care for it. Our non-CAH daughter, 2 3/4 years, has only taken formula or water, and doesn't really care for juice. We have not had a problem with her hydration; she likes her water (we replaced her pacifier with a sippy cup at 13 months), so you may want to encourage the water. Or, dilute the juice, 1/2 water, 1/2 juice, or mix some of the juice (just a touch, for flavor) in expressed breast milk, and bottle feed him a few times, until he gets used to the different taste. Just a suggestion; one that the nurse gave us when our son wasn't drinking. Good luck.