A year after two ‘Once in a Century Storms’: Where does Mississauga stand today?

It’s been one year since the skies over Mississauga deposited wave after wave of water below, triggering not one, but two “100-year storms” just weeks apart. Streets became rivers. Basements were swallowed whole. Highways shut down. Entire neighbourhoods were thrown into disarray.

On July 16, 2024, Mississauga resident Ruel Suazon faced what he called the “worst” flooding in his 35 years living on Queen Frederica Drive.

His home, which backs onto Little Etobicoke Creek, was hit hard when 106 millimetres of rain fell in just a few hours. 

Toronto and Region Conservation Authority’s (TRCA) Rathwood precipitation gauge station recorded an “equivalent of a full bathtub of water for every square meter in just one hour, overwhelming rivers and urban drainage systems and causing flash flooding.”

Water poured into Suazon’s fully finished basement, destroying everything.

“Everything was flooded and damaged,” he recalled at a public flood information session held at the Living Arts Centre in November, attended by over 250 residents. It marked the third time his home had flooded.

After last summer’s severe weather events The Living Arts Centre hosted a public session to detail Mississauga’s response to more intense and frequent storms.

(City of Mississauga/X)

He wasn’t the only one. 

Resident Karri Siemms watched as the creek behind her home surged over its banks and swallowed her backyard. Within minutes, water breached the Applewood Hills Greenbelt trail and rushed toward her house.

“So that ensued to panic,” Siemms told The Pointer in May. 

She and her son raced to move electronics and try to shovel water away as it pushed into their basement. “The first one was pretty quick, and then it’s like nothing happened,” she recalled. “By 1:20, the sun’s out. By five o'clock, we were sitting there going, ‘Did that really just happen?’” 

But there was more to come.

On August 17 and 18, up to 170 millimetres of rain drenched parts of Mississauga and the GTA. 

For Siemms and her husband, Craig, it was a painful repeat of 2013; another basement lost to floodwater, another round of rebuilding. 

“I lost so much,” she said. “So much.”

In both storms, streets and highways flooded, trapping residents in vehicles and forcing the evacuation of over 100 seniors from Tyndall Seniors Village. The damage to homes, businesses, and infrastructure was widespread and long-lasting.

During the flooding last summer, emergency services were dispatched from multiple parts of the city to respond to overwhelmed areas, but with calls mounting and roads submerged, many residents were forced to rely on neighbours and community members for help, including those whose vehicles were stranded in rising waters.

(City of Mississauga)

For many, the financial toll has only compounded the trauma. 

One senior resident, who asked not to be named, shared that she and her husband lost "everything", washer, dryer, furnace, water heater, rugs, furniture and appliances, when 12 inches of sewer water filled their basement. Insurance covered a small portion of the loss. 

“We had no air conditioning, and we had no hot water for three weeks, which is a long time,” she added.

Suazon echoed the same frustrations, still dealing with insurers months later. “It’s hard to deal with these kinds of losses, especially when you've worked so hard, piece by piece, to build your life here as an immigrant,” he said.

According to the Insurance Bureau of Canada, the flooding in Ontario this summer caused more than $1 billion in insured damage, with $940 million from the July storm alone, making it the second-costliest flood season in the province’s history.

In September 2024, Mississauga Council approved a city-wide Flood Mitigation Action Plan, with targeted initiatives across multiple wards.

In Ward 1, where both Suazon and Siemms live, the City initiated a capacity review of the trunk storm sewer near Harvest Drive to address overflows from Little Etobicoke Creek. 

In Ward 3, staff began a comprehensive riverine flooding review upstream of Dixie and Dundas, including feasibility studies for detention ponds near the Tyndall Seniors Home and a possible creek diversion.

Flooding near the Dixie and Dundas corridor in 2024.

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The City also moved ahead with land acquisition for the Dixie-Dundas Flood Mitigation Project, which includes replacing the Dundas Street East bridge, a key recommendation from a 2021 Toronto and Region Conservation Authority study. The project is fully funded in Mississauga’s capital plan, with an estimated cost of $8.3 to $9.5 million. 

In Ward 5, the Historic Malton Village saw design work start for sewer upgrades on Cattrick and Hull Streets to reduce flooding and outlet blockages. 

In Ward 10, a downspout disconnection pilot moved ahead in Black Walnut Trail, and the design of the fourth pumping station was fast-tracked in Lisgar.

An investigation was launched for flooding in North Streetsville, with a sewer capacity review slated for this year in Ward 11.

To manage the flood response workload, Council also approved funding to hire more contract staff and, in November, backed a $30-million increase to the 2025 stormwater budget, which includes 20 new full-time positions for infrastructure maintenance and mitigation. 

Another $10 million was allocated to sewer upgrades in Malton.

Despite this progress, City officials issued a stark warning last year: Mississauga’s stormwater reserves could be depleted by 2026 without new sources of revenue. 

At a council meeting in November, interim infrastructure planning director Emma Calvert said the City may need to increase stormwater charges or divert future provincial and federal grants to these critical projects.

Calvert also unveiled the City’s 10-year capital plan, outlining $365 million in stormwater infrastructure investments through 2034 for projects like upgrades to storm sewers along the Dundas BRT corridor, drainage improvements in Port Credit, Credit River erosion control estimated at $2.8 million by 2029, and stormwater pond dredging and Cooksville Creek restoration projected to cost $7.8 million in 2032.

The City completed a flooding evaluation study of the Little Etobicoke Creek watershed in 2021.

(City of Mississauga)

Some emergency work has already been completed, including the installation of a 1.2-metre temporary floodwall along Little Etobicoke Creek, a major sewer inlet upgrade near Tonolli Drive just north of the Queensway, and a check valve along Cooksville Creek to prevent dangerous backflow.

A 1.2-metre floodwall was installed along Little Etobicoke Creek.

(City of Mississauga) 

The City has also rolled out real-time monitoring for 1,300 stormwater inlets, identifying 70 as high-priority locations. These sites, once cleaned just twice annually, are now inspected weekly and cleared after every major rainfall.

In a statement shared with The Pointer, the City noted sewer lines are assessed every five years using CCTV-equipped robots to detect blockages or damage early.

(City of Mississauga)

Mississauga’s Climate Change Action Plan warns that by 2050, storms like the ones in 2024 will occur every six years instead of every 40. Annual rainfall is projected to increase by 70 millimetres. “Extreme events like lightning and thunderstorms, snowstorms, freezing rain, hail, powerful winds, droughts, wildfires, flooding and storm surges are expected to become more intense,” staff previously told The Pointer.

To help residents protect their homes, Mississauga introduced two major rebate programs launching in February 2025. The Basement Flooding Prevention Rebate will provide up to $7,500 for eligible improvements like sump pumps or backwater valves. The Flood Resilience Rebate will cover 50 percent of costs, up to $3,000, for water-resistant materials or other flood protection improvements.

An existing Region of Peel rebate of $1,500 also remains available for installing sanitary backwater valves.

Council also approved a $1,000 Residential Compassionate Flood Relief Grant for those impacted by the July and August storms. Though residents say it’s not enough, many called it a helpful first step. “Anything helps, but will it fully reimburse us? Absolutely not,” one resident said.

To extend the support, Ward 3 Councillor Chris Fonseca successfully motioned to increase the rebate cap by $500,000, raising it to $1.5 million, and expanded eligibility to include flood events dating back to 2013.

Fonseca has been a leading voice on the issue, calling in July for enhanced collaboration with the Region of Peel and conservation authorities. Suazon praised her for staying connected to affected residents and advocating for action.

So far, Mississauga has invested over $265 million in stormwater upgrades since 2016 and committed $311 million more through 2034.

Is it enough? 

A 2022 report from the Financial Accountability Office of Ontario warns that climate-induced extreme rainfall could cost municipalities an additional $700 million annually just to maintain existing stormwater systems. Without immediate upgrades, overall infrastructure costs could rise by 27 percent. 

The report emphasized the urgent need for higher-capacity systems and green infrastructure solutions like rain gardens, bioswales, and permeable surfaces before the impacts become irreversible.

Mayor Carolyn Parrish and City officials have made it clear they’re acutely aware of the funding shortfall. On November 13, 2024, Parrish stated bluntly that Mississauga has been “left dry” by both Queen’s Park and Ottawa.

The provincial and federal governments announced multi-million-dollar flood resilience packages for Toronto and Brampton, but Mississauga received no comparable support. 

In response, Parrish launched a grassroots letter-writing campaign, providing residents with pre-stamped and pre-addressed letters to send directly to Premier Doug Ford, demanding urgently needed infrastructure funding.

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