I called Ottawa to find out what exactly they put in our water.
I had one of the people who actually treat the water call me up to answer my questions! That was really cool.
Anyway, she gave me this website, which lays out exactly what's added:
https://ottawa.ca/en/living-ottawa/water/drinking-water/drinking-water-quality-annual-reports-and-test-results
Ottawa proper uses the Britannia and Lemieux treatment plant. Thought I'd share