The owner of the Indian Point nuclear power station says one of its two idled reactors is back in service.
Indian Point 3 had been offline since a leak of non-radioactive water was spotted on Thursday. Owner Entergy Nuclear said it went back on the grid Monday morning.
The double outage meant the New York metropolitan area was without one of its largest sources of power. But mild weather kept energy demand well below peak levels.
The power station is in Buchanan, about 35 miles north of Manhattan.
Indian Point 1 was mothballed in the 1970s.