Jackie,
If there is no seeping or leakage and the level of water inside is good, you should be in good straights. The concern in rehydrating is whether or not there is a proper seal. The longer that barrel sat before use, for instance, and especially without any plastic wrap to attempt to hold moisture in, the more the barrel would dry out and leakage can become a concern.
I normally wait for two days to verify, but if the outside of the barrel is essentially dry and inside is all full of water, it sounds like you're good to go. Be sure and verify that the stopper isn't wicking liquid out as welll, though.
- Jim