Reason 1: pre-1960 housing stock
Roughly 40% of Vancouver's housing stock predates 1960. That stock was built before modern rodent-exclusion standards entered the BC Building Code. Soffit detailing, vent screening, foundation perimeter sealing, utility penetration treatment — all standard on post-1985 homes — were ad-hoc on pre-war and mid-century construction. Walk any East Vancouver craftsman, Kitsilano four-square, or Marpole bungalow and you'll find 8-15 rodent-accessible entry points without trying. Newer homes have 2-5 on average. The structural difference compounds at the city level: more old homes equals more total entry points equals more rat-supportable habitat.
Reason 2: never-freeze winters
In Winnipeg, three weeks of −20°C reliably culls juvenile rats and reduces overwintering populations. Vancouver almost never sees this. The climate stays above freezing through most winters, with brief cold snaps that don't last long enough to substantially impact rat populations. The result is multi-generational continuous breeding — rats that would die in colder Canadian cities simply don't, here.
Reason 3: the 2023 SGAR ban
The 2023 BC ban on second-generation anticoagulant rodenticides removed the fastest-acting bait class from the residential pest-control toolkit. The remaining options work, but they kill more slowly and require multiple feedings. The visible effect: more daylight rat activity (rats survive longer between feedings, foraging in conditions they'd previously avoid), more opportunistic nesting, and shifts in how property managers maintain ongoing pest contracts. The net effect on absolute population is debated; the effect on visible activity is unmistakable.
Reason 4: Vancouver Bylaw §3.1 and individual responsibility
Vancouver Bylaw §3.1 places rodent control responsibility on individual property owners. There is no city-wide structural inspection mandate, no zoning-level pest control coordination, no organized neighbourhood-scale exclusion programme. Toronto and parts of New York operate city-funded baiting and inspection regimes; Vancouver does not. The result is a patchwork — some streets have well-maintained homes with low rat pressure, others have a single under-maintained property that supports a colony for the entire block. Individual responsibility means rat populations track the worst-maintained 20% of stock on any given street.
Frequently asked questions
Are there more rats now than 10 years ago?+
Do other Canadian cities have less rat problem?+
Can a single homeowner reduce rats on their street?+
Is the City of Vancouver doing anything?+
A fifth factor the headlines miss: construction displacement
Metro Vancouver's relentless densification and construction churn creates a recurring rodent displacement event. When a 1950s bungalow is demolished for a six-storey strata, the established Norway rat colony under the slab doesn't disappear — it redistributes to the adjacent properties. Every major construction project in Vancouver displaces dozens to hundreds of rodents into surrounding blocks. The 2020-2026 construction cycle in East Vancouver, South Granville, and Mount Pleasant has been the largest in the city's history — and rodent callouts from those corridors track construction starts with a roughly 6-week lag. This isn't speculation; it's a documented pattern in our own booking data.
What you can control vs what you can't
You cannot control your neighbours' maintenance standards, the city's construction pipeline, or the provincial climate. You can control the entry-point density of your own building envelope. A properly sealed Metro Vancouver home resists rodent pressure even when the street-level population is high. The analogy is a well-waterproofed basement in a flood zone — you can't move the river, but you can control whether water gets into your house. Exclusion is the equivalent for rodents. It doesn't solve Vancouver's population problem; it solves your home's problem. Read our full exclusion approach at [How to Rodent-Proof Your House](/guide/how-to-rodent-proof-your-house).