Puget Sound Engery said it had restored electricity to all but 1,499 customers on Bainbridge Island by 2:30 p.m. Tuesday.
Power went out for roughly 5,000 homes and businesses on Bainbridge just before noon Feb. 6.
All of the island should have power restored by 3:30 p.m. Tuesday, said PSE spokeswoman Andrew Padula.
The outage was caused when PSE took its Murden Cove substation offline after finding oil leaking from one of the transformers at the substation, Padula said.
Power was cut in order to determine what was causing the leak.