I don't think that's perfectly done. I was hiking on the North Shore in Vancouver and there's a sign over a stream warning about untreated sewage. If it's a problem in the one of the biggest and wealthiest cities, I can easily see it being an issue in smaller towns.

In very rural areas, especially on reservations, I believe water and sewage treatment is an ongoing issue.

Most towns do, occasionally - overflows happen. Article is from 2018 but I assume nothing has radically changed since then.

https://www.cbc.ca/news/canada/toronto/ont-enviro-report-1.4...

In my city we JUST started treating our sewage: https://www.cbc.ca/news/canada/british-columbia/victoria-sew...

Thanks for the info, that is genuinely surprising. And Victoria is not some poor town either. I guess there wasn't much incentive to improve given the consequences of inaction were dumped literally on someone else's doorstep.

This might be specific to very old cities, but New York City has a combined sewage and storm water system. Sewage ("black water") and rainwater from the streets goes through the same output processing. When it rains a lot, the system can't cope, and the water (sewage and all) is discharged into the Atlantic.

AFAIK, most of the cities on the west coast of Canada dump untreated sewage into the ocean.