London homeowners deal with flooded basements in aftermath of 'freak storm' rainfall

Tora Klassen has spent hours over the last two days cleaning up her basement that was flooded following Monday's historic torrential downpour in London. 

Water quickly poured down a hill behind her house in Old South and formed what looked like a lake in her backyard, Klassen said. She managed to reduce permanent damage and divert water from her basement to nearby storm drains, but that didn't come without hassle.

"It was completely disruptive to our entire day," she said. "It takes a lot of time and energy and when you have young kids, it's stressful trying to balance the running of a home in addition to the burden of cleanup from these kinds of things."

The ordeal also resulted in a loss of income for Klassen and her husband, who rent out one of their basement suites as an Airbnb and had to cancel a Monday night booking, she added.

Monday's heavy rainfall broke London's century-old weather records, with a total of of 59.3 mm of rain, compared to the previous record of 45.2 mm set in 1923, Environment Canada said.

The Upper Thames River Conservation Authority said that up to 60 mm of rain fell in areas north of London on Tuesday morning. Environment Canada reports the record rainfall for July 16 in London at 43 mm in 1988.

Widespread flooding on Tuesday also caused several power outages and closed major highways in the Greater Toronto Area. Hwy. 402 was also closed for a time and organizers cancelled an outdoor comedy festival scheduled for this weekend because of flooding in Harris Park. 

Call volumes up for restoration companies 

Call volumes for water damage in the London and St. Thomas areas increased six-fold at Restore, Renovate, Build, with staff working around the clock, said company director Danielle Perelman.

"This flood was totally unprecedented. Hurricane Beryl had come through last week and we all felt like we had some warning and had people on staff ready to respond, whereas this was a bit more of a freak storm," she said. 

Perelman's team has gone to houses where water is knee deep, damaging window wells and roofs, as well as clogging floor drains and overflowing outdoor swimming pools.

Basements are usually the first to be impacted by rain storms and aren't equipped to handle water damage, said Glenn McGillivray from the Institute for Catastrophic Loss Reduction.

"We build our basements really nicely, we put expensive features and furnish them but it doesn't take much to destroy these things. All you need is a couple centimetres of water and a basement can be completely gutted," he said. 

A previous flood last year caused extensive damage to Klassen's basement and took two months to repair. She said most houses on her street were flooded on Monday.

Tips to mitigate floods

Damage to floors, drywall, ceilings with potlights and furniture can cost tens of thousands of dollars in repairs, McGillivray said, adding that higher water levels can lead to electrical problems, with most panels usually located in basements.

Health issues can also arise from storm water entering basements through sewage systems, with water often contaminated with E-Coli. When combined with humidity, the conditions allow for mould growth, McGillivray warned.

He recommends homeowners install backwater valves to prevent wastewater from entering basements, along with sump pumps that remove accumulated water. It's important to ensure downspouts, or vertical pipes in gutters, and eavestroughs are cleaned so they don't overflow, McGillivray said. 

"If you have chronic basement flooding, we suggest you don't put anything fancy or important down there and don't finish it all beautifully without putting these mitigation measures into place," he said. 

Worsening climate change and development on wetlands meant to absorb water will likely increase the frequency of flash flooding in the future, McGillivray said. Klassen agrees and said flood impacts on homeowners need to be included in the city's climate emergency action plan. 

"This idea that 'I don't live near a body of water so I'm OK, I won't flood' needs to be reconsidered. If it rains where you live, you can experience flooding," said McGillivray.