"It is the first time in 100 years that's the case," Tahuna outfall project manager Brian Turner said yesterday.
Since the Tahuna outfall pipe was commissioned on January 23, the council had tested water from between Second beach, near the St Clair pool, and Smaills beach.
"To date, it indicates [all] the beaches are safe to swim," Mr Turner said.
So safe, Dunedin Mayor Peter Chin and Dunedin City Council infrastructure services committee chairman Cr Andrew Noone joined Mr Turner for a celebratory swim.
"The water was very clean and the beach certainly looks very nice," Mr Chin said afterwards.
Asked about his health following the dip, a laughing Mr Chin said: "I feel very well."
The outfall pipe is part of a project to take effluent discharged from the Tahuna sewage-treatment station and dispose of it 1.1km out to sea.
It will be followed by the construction of a new pumping station with chlorination and odour control facilities at the Tahuna plant.
Stage two of the project - expected to be finished in 2011 - is the installation of a $67 million secondary-treatment system at the plant.
Mr Turner said he stood at Lawyers Head last Saturday and saw only water that was "crystal clear".
At the moment, the current was moving from west to east, which used to push sewage towards Tomahawk.
It had not yet moved in the opposite direction, which pushed sewage towards St Clair and closed beaches on that side of Lawyers Head, since testing began, but at the moment the sewage plume from the pipe was doing what modelling done in 2004 suggested it would.
Apart from beach testing, the pipe itself had been tested for leaks and passed those tests.
The next step was to chlorinate the sewage, which would be done in mid-March, to be followed by a report on options for the secondary treatment plant then going for consideration by council.
