Investigations into contamination of water supply in the capital of the Isle of Man last week have revealed the cause.
Properties between Church Street and North Quay in Douglas were not able to use water for drinking, cooking or washing since Friday.
It was due to sea water being pumped back into the fresh supply, during a routine procedure washing the ferry Ben-my-Chree, entering the area's system.
The Steam Packet Company said it has never happened before, and that it was a 'genuine accident.'
Residents were told on Friday evening that the issue had been resolved.