Six days after a rainstorm caused flash flooding across Toronto, city crews were still trying to figure out what happened at Mary Raimondo-Parato's North York home.

Workers from the city of Toronto's water department were at her property on Seabrook Avenue, near Jane Street and Highway 400, for the fourth day in a row, she said. They were digging a hole on the front lawn to find out why her basement flooded with sewage for the second time in five years.

It's a situation she didn't think she would have to go through again because her family followed the recommendations of city staff and made upgrades to reduce the chance of flooding after her home flooded the first time.

"We're faced with another horrible nightmare ... having to repair what we were told we wouldn't have to do again," said Raimondo-Parato.

The incident raises the question of whether the city has done enough to help residents who are vulnerable to flooding during major storms, especially as scientists predict intense rain and flooding will become more frequent in southern Ontario due to climate change.

Flooded basement for the second time

Raimondo-Parato's home is located in a low-lying area near Black Creek that the Toronto and Region Conservation Authority considers a "highly flood vulnerable area."

Her house — along with most others on her street — flooded after a similar storm on June 8, 2013 dumped 126 millimetres of rain on Toronto in a two-hour period, flooding basements, downing trees and halting both subway and airline service.

An Insurance Bureau of Canada report later found that storm caused an estimated $65.2 million in water damage and cost insurers $850 million.

After that storm, Raimondo-Parato said her family paid for engineers to assess what went wrong and installed a backflow-preventer valve on the advice of city officials. The city also repaired the main drainage system in 2016 and reassured residents that flooding would no longer be an issue, she said.

But it still wasn't enough to stop the water from seeping into the Raimondo-Parato's basement last Tuesday.

City crews dug a hole a couple of metres deep in the front lawn of Mary Raimondo-Parato’s North York home. (Paul Smith/CBC)

Raimondo-Parato said workers were playing a "guessing game" trying to pinpoint the source of the problem.

"Look at what they've dug up already," she said, gesturing to a hole in her front yard a couple of metres deep. "They haven't even been able to dig in the correct area, in terms of finding the problem and rectifying the problem."

While her neighbours experienced some water damage during last week's storm, it was not as severe and damaging as the 18 inches of sewage water that flooded Raimondo-Parato's home. It's not clear why her house flooded but others didn't.

"My neighbours didn't get what I had," said Raimondo-Parato. "The smell was unbearable … It was too much to handle."

Now, she's worried that after submitting a second massive claim her insurance company will drop her family because they are too "high-risk."

She questioned whether the contractors hired by the city to repair the drainage system in 2016 made a mistake that is now going to cost her family.

Raimondo-Parato said workers over the weekend used a robotic camera and found four "crystal clear" misalignments at the point where the pipes from her house empty into the main drain for the entire street. That, she said, might have caused her house to be affected by flooding and not others on her street.

She said her insurance company is going to go after the city for the damages because "this should not have happened again."

Local councillor gets an earful

Coun. Frank Di Giorgio of Ward 12, York South-Weston, also visited the property Monday — and he got an earful from Raimondo-Parato.

"You have no idea the disaster, the impact!" she said to the councillor. "This is not right that now we have to endure this for the second time."

Mary Raimondo-Parato speaks with Coun. Frank Di Giorgio about the impact of flooding on her home. (Paul Smith/CBC)

Di Giorgio said he was at a loss to explain what happened.

"This was identified as one of the problem areas that required some infrastructure improvement," said Di Giorgio. "And it was one of the high priority areas that we actually managed to address."

He told Raimondo-Parato he would be calling for a review of what happened.

"In a situation like that where everyone has done exactly what they're supposed to do but the problem persists… the city needs to go back to: 'what was the cause of the problem?'" said Di Giorgio.

He said it is too early to say whether the city will provide any form of compensation because they must first identify what the cause of the flooding was, and whether there is any liability for the city,