Halifax Mayor Peter Kelly splashes around in the harbour Wednesday. (CBC)

Halifax Mayor Peter Kelly has taken his first dip in the harbour since the $54-million sewage treatment facility was repaired.

Kelly splashed around at Black Rock Beach on Wednesday, making good on his promise to swim in the harbour once the sewage plant was working again this summer.

"The system is working. The water is clean," he told reporters after his dip off Point Pleasant Park.

The mayor said it would take time to build public confidence in the water and the city's ability to keep it safe. He hoped his trip to the beach would bolster that confidence.

"The fact is that it's clean, it's okay to do. Some people have been in there swimming and some have done it often," he said.

In August 2008, Kelly took a well-publicized swim to signal that the city's new sewage treatment system was operational and the era of dumping raw sewage into the water was over.

But that photo opportunity turned sour months later when the plant suffered a catastrophic failure in January 2009.

A power outage caused the plant to flood with raw sewage, and the facility was knocked out of service for a year and a half.

The municipality says the $11-million repair bill is being covered by insurance.