I live in Edmonton, Alberta. In the last 10 years the only rats I've seen are the ones used in the neuroscience labs at the University of Alberta.

In truth, my house got a infestation of the smaller deer mouse [1], 2 years ago. But they are indigenous to Alberta and much smaller and easier to catch than the brown rat. It was quite easy to get rid of them, a cleaning in the garage and some traps did it.

[1]https://en.wikipedia.org/wiki/Peromyscus

I lived there for decades and never saw a rat. I guarantee they have rat infestations occasionally, but they are caught and eradicated pretty quickly. I know they had one down near Lethbridge recently, but I think it turned out to be pet rats that were let loose and started breeding.