Swimmers can get back in the water at the Black Rock and Dingle beaches, Halifax Water announced Friday.

Test results of water samples taken Wednesday in Point Pleasant Park and Fleming Park show that fecal coliform levels are well below swimming level guidelines, Halifax Water spokesman James Campbell said Friday in a news release.

The tests indicated levels of four colony forming units per 100 millilitres of water at Black Rock Beach, and five colony-forming units per 100 millilitres of water at Dingle Beach - well below swimming level guidelines of 200cfu/100ml for fecal coliforms.

The quality of harbour water has improved dramatically, Campbell said, now that the Halifax, Dartmouth and Herring Cove wastewater treatment facilities are all operational.

"This is the culmination of a project residents have pushed hard for over many years," Mayor Peter Kelly said in the release. "Restoring our harbour and these beaches is a legacy we can all be proud to pass onto our children."

This is the second time in recent years that metro beaches have been opened to swimmers. In August 2008, Kelly took a swim at the Dingle in the newly clean harbour waters, thanks to a $333-million sewage treatment project.

But in January 2009, the $55-million Halifax treatment plant was disabled by a power failure that caused catastrophic flooding just weeks after the city took ownership. It resulted in raw sewage once again flowing directly into the harbour.

The plant was finally operational again in June, and Kelly said repairs cost about $10 million.

The three Harbour Solutions Project plants are designed to treat four times the average dry weather flow. This means following a heavy rainstorm, flows entering the treatment facilities may temporarily exceed the design capacity, Campbell said in the news release.

When this happens, the excess flows are screened through the combined sewer overflow chambers to remove floatables, and then discharged into the harbour, he said.

Following heavy rain, swimmers should not swim in the harbour for three days.

HRM beach staff will take water samples to verify water quality following overflows and announce when swimming is safe.

"As we learn more about how the harbour reacts to overflows, the three-day period could be reduced," Campbell said.

Halifax Water board chairwoman Colleen Purcell urged Haligonians to take advantage of the safe harbour water.

"Bringing these two historical swimming spots back to the community is great news for everyone. I hope residents and visitors alike take advantage of these beautiful beaches and parks," she said in the release.