The Horizon Health Network said services at the Hotel Dieu of St. Joseph's Hospital resumed Tuesday after it closed last Wednesday.
But the health board said oncology patients with appointments for Tuesday were told to go to the Upper River Valley Hospital in Waterville for treatment.
Patients who were moved to the hospital in Waterville last week will be returned to Perth-Andover, but Horizon Health said late Tuesday that will be delayed because rain has been forecast over the next couple of days.
A large ice jam passed through Perth-Andover on Sunday and water levels have stabilized.
But River Watch officials say people should remain on alert because of rain and warm temperatures forecast for the next several days.