Toronto Is Canada's Rattiest City Again — Why GTA Rat Activity Surges This Summer (2026)

Quick answer: Toronto again ranks as Canada’s rattiest city, and research points to rat numbers climbing across the GTA. Summer is when outdoor rat colonies breed fastest, building the population that pushes indoors in fall. The standard for a well-run property is zero rat activity — so the time to inspect and seal pressure points is now, before the autumn migration.

If you keep a tidy home or run a clean business, a rat is not a “city problem you tolerate” — it’s a breach. Rats gnaw structural wood and wiring, contaminate food-prep areas, and breed quickly once they find shelter. And the regional backdrop is moving the wrong way: Toronto continues to top Canada’s rattiest-cities rankings, and the GTA’s warming winters are letting more rats survive year to year. This is a calm, sourced look at what’s happening and what to do about it this summer.

What’s happening with rats in the GTA right now?

Toronto again ranked #1 on Orkin Canada’s most recent Rattiest Cities list, and reporting tied to that data noted rodent-related complaints in the city have climbed sharply over the past decade. Warmer winters mean more rats survive into spring, and summer breeding then compounds the population.

Here is the situation at a glance:

What’s happening	What it means for you	What to do
Toronto tops Orkin’s rattiest-cities ranking again	Regional rat pressure is high and rising	Treat zero activity as the standard, not luck
Summer = peak outdoor breeding	Today’s yard colony is fall’s indoor invasion	Inspect and remove harbourage now
Warming winters aid survival (per climate researchers)	Fewer winter die-offs, bigger spring base	Don’t wait for cold weather to act
Construction & development disturb burrows	Rats relocate into adjacent homes/yards	Watch for new burrows near foundations
Your time (DIY route)	Repeated trap checks, sealing, relapses	Weigh hours and risk against a managed program

Why is Toronto consistently Canada’s rattiest city?

Toronto’s mix of dense housing, abundant food waste, ongoing construction, and increasingly mild winters is close to ideal for Norway rats. Orkin Canada, which compiles the ranking from the volume of rodent treatments it performs, has placed Toronto first repeatedly — a signal of sustained, region-wide pressure, not a one-off bad year.

A 2025 study published in the journal Science Advances documented rising urban rat populations in most major cities it examined, linking the trend partly to warming temperatures — and Toronto was among the cities showing significant increases. The takeaway for GTA homeowners: this is a structural, climate-assisted trend, not a passing spike.

Why does rat activity peak in summer if rats invade in fall?

Summer is when outdoor rat colonies breed most aggressively, with abundant food and warmth. That population build-up is exactly what drives the well-known fall push indoors as temperatures drop. So the quiet summer months are when the pressure that floods basements in October is actually being created.

This is the practical reason to act now rather than in September. Reducing harbourage and food sources in June and July shrinks the colony before it has a reason to come inside — far easier than evicting an established indoor population in the fall.

What to check around your GTA property (6 steps)

Walk your foundation for burrow holes (about the size of a toonie or larger) near walls, decks, sheds, and garden beds.
Secure food sources — bird seed, fallen fruit, pet food, and unsealed compost are rat magnets in summer.
Tighten garbage and green-bin lids and keep bins off the ground where possible.
Cut back vegetation touching the house; overgrowth gives rats cover to travel unseen.
Check gaps around utility penetrations, vents, and garage door seals — rats exploit openings larger than about 1.5 cm.
Note any droppings, gnaw marks, or runways along walls, and book an inspection before fall if you find them.

Rats vs. mice: don’t assume it’s the same job

Rats are larger, stronger gnawers than mice and often nest outdoors in burrows before moving in, which changes the inspection and treatment approach. If you’ve read our guidance on mice control in Toronto or mice control in Mississauga, know that a confirmed rat problem warrants a tailored plan — see our residential pest control service for how we assess rodents on-site. That includes the rat-prone west-end pockets we cover with pest control in Etobicoke.

Why Sani IQ

Sani IQ is a licensed, science-based Ontario pest-control company built on Integrated Pest Management — we inspect, identify the species and entry pressure, and treat with commercial-grade bait stations, not guesswork. We’re a local operator with 100+ five-star reviews and our Pest-Free, OR It’s Free guarantee. For homes facing high rodent pressure, year-round protection is the standing recommendation; businesses can stay inspection-ready with our commercial pest control in Toronto. See transparent pricing on our plans and pricing page.

The bottom line

Toronto’s rat numbers aren’t a rumour — they’re tracked, ranked, and trending up with a warming climate. In a well-run home or business, zero rat activity is the standard, and summer is the cheapest, easiest time to protect it before the fall migration. Book it and forget about it: call (705) 302-1887 or request a quote at our contact page.

Frequently asked questions

Is Toronto really Canada’s rattiest city in 2026? Toronto again topped Orkin Canada’s most recent Rattiest Cities ranking, which is based on the volume of rodent treatments the company performs. Reporting also noted Toronto’s rodent complaints have risen sharply over the past decade, and research links rising urban rat numbers to warming temperatures.

Why are there more rats in the GTA lately? Milder winters let more rats survive year to year, and dense housing, food waste, and ongoing construction provide shelter and food. A 2025 Science Advances study tied rising urban rat populations partly to warming temperatures, with Toronto among the cities showing increases.

When are rats most active in Ontario? Outdoor rat colonies breed most aggressively in summer, building the population that pushes indoors as temperatures fall. That makes summer the ideal window to remove harbourage and food sources before the autumn indoor migration begins.

How do I know if I have rats and not mice? Rats are larger, leave bigger droppings, and often nest in outdoor burrows near foundations, decks, and sheds before moving in. Gnaw marks on wood, greasy runways along walls, and burrow holes the size of a toonie or larger point to rats rather than mice.

Should I handle rats myself or call a professional? DIY usually means repeated trap checks, sealing, and relapses over weeks, with rats often re-entering from outdoor burrows. It’s a time-and-risk trade: a managed program inspects, targets the colony, and is backed by our guarantee — which store traps are not.