Not many homes in Halifax have a secret staircase that tunnels down four storeys to a vast concrete cavern.

But stepping inside the modest brown house on Duffus Street, it's clear this isn't a normal home.

The building is owned by Halifax Water, and is used to conceal the entrance to a tunnel that descends into a pumping station hidden beneath Barrington Street.

"It was designed to fit into the neighbourhood so it wouldn't be as intrusive or ugly," said Jake Fulton, a spokesperson for Halifax Water.

In this underground space, three Halifax Water pumps have failed in the past two months. That has led to warnings about swimming in the harbour, and requests for residents to limit how often they flush their toilets.

The underground pumping station uses powerful and complicated equipment to perform a simple task: lift sewage higher.

Everything flushed down toilets, emptied from bathtubs, or drained out of washing machines, flows downhill through pipes to treatment facilities. But along the way, those gravity-powered pipes end up below the level of the destination facility, said Fulton.

That's why the city has pumping stations.

The Duffus Street facility — and dozens more like it — collect wastewater in a giant basin. Water flows from Larry Uteck, Clayton Park, Fairview, and the north half of the peninsula into the Duffus Street pumping station.

"Here a pump raises it to another point in the system, so it can then flow by gravity to the wastewater treatment facility," Fulton said. 

Typically, the facility has two pumps installed to move sewage up three huge pipes. Two pumps — in case one fails.

One did in late June, leaving just the backup pump to move wastewater. On July 19, the backup failed too.

"We worked as quickly as we could to find an alternative pump," said Fulton. "On the 22nd of July, we had the system back up and running on a replacement pump.

"Then that replacement also failed."

That meant untreated but filtered wastewater was flowing into Halifax harbour.

"It's been a series of unfortunate events with pumps here at the Duffus Street pump station," Fulton said.

With the pump failures, wastewater and stormwater gathering at the pumping station had nowhere to go.

The only option was to send it into the harbour.

"So as the wastewater leaves the facility here, it goes through a screen process that removes any solid waste, but any bacteria is still entering the harbour," said Fulton.

That could be a health risk, which is why Halifax Water is warning residents about using the harbour.

"We're not advising anyone to use the harbour for recreational purposes, and to avoid contact with the harbour if possible," said Fulton.

He also reminded residents who have their wastewater flow through Duffus Street to try to limit the amount of times they're flushing their toilets.

To reduce the potential environmental impact during this repair, Halifax Water is asking customers in the areas shown on the attached map to reduce the amount of water they are flushing and pouring into their drains. To learn more, visit <a href="https://t.co/XlU3AvdhTL">https://t.co/XlU3AvdhTL</a>. <a href="https://t.co/S26Q7BdpLg">pic.twitter.com/S26Q7BdpLg</a>

As of Tuesday evening, a team was working to prep another 300-horsepower industrial pump to be installed at the Duffus Street location.

The main issue with moving, installing and transporting these pumps? Their size.

"We need to winch the pump about 20 metres down to here," Fulton said, pointing to a pit extending down from the surface to the top main floor of the wastewater basin.

Even once the pump arrives, it's a process to install it. Measuring about two metres tall, "it'll barely fit through the hallway," said Fulton.

"It's certainly not an easy job but we're working on it," he said. "Everyone involved is doing their absolute best to get the system back to normal."

Emergency repairs were completed Tuesday night, but the system was again quickly overwhelmed "and clogged with rags and wipes." In a news release on Wednesday, Halifax Water said crews were working to unclog the pump. 

Officials have renewed their calls for residents to be careful what they flush down the toilet, and say they will now work to develop a plan to deal with this latest pump failure.

We continue to ask customers in the impacted areas to reduce the amount of water they are flushing and pouring into their drains. This will help minimize the amount of wastewater released into the environment. To learn more, visit <a href="https://t.co/JTJU3cneSb">https://t.co/JTJU3cneSb</a>. <a href="https://t.co/EERXSS3ZE7">pic.twitter.com/EERXSS3ZE7</a>

Brett Ruskin is a reporter and videojournalist covering everything from local breaking news to national issues. He's based in Halifax.

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