The overflow of sewage into the harbour is part of the treatment plant's normal operations. CBC

Halifax is pumping raw sewage into its harbour again and blames heavy rain for the unsanitary conditions.

The steady deluge Halifax has been receiving for the last few weeks has overwhelmed the capacity of the city's wastewater treatment facilities several times this month.

Halifax Water spokesman James Campbell said Thursday that sewage has been pumped into the harbour as part of normal design.

"The combined sewer overflow chambers kick in. They screen all the floatables out and discharge the rest of the water until the plant settles down below maximum capacity and then the chambers shut down," he said.

Campbell said protracted light rainfall isn't a problem, but short bursts of heavy rain overwhelm the system. While the beaches aren't open right now, Campbell said any early dippers should hold off.

"If somebody was inclined to go for a dip in the chilly water, we would recommend they not do it [but] wait for three days following heavy rain," he said.

Decades of pollution

Halifax pumped raw sewage into the harbour for decades before opening a $55 million treatment plant in 2008, followed by the opening of harbour beaches to much fanfare.

The plant flooded and stopped working in 2009 and the beaches were closed again until the plant got back online in June 2010.