Canadians drink tap water directly. So if something goes wrong and bacteria get into water, a lot of people get ill. But a greater and less noticeable danger is lead, which gets into tap water in our own houses.
Lead plumbers were used before the 20's. Lead connectors were used until the 60's. It can only be removed by proper filter, not boiling. It doesn't affect adults too much, but can do great demage to children.