It doesn’t. Some of the Swiss waters are very good. My baseline for coffee is quality single origin Geisha, and good Swiss water is better than most espresso places.
In the UK I use Redber for beans, I drink decaf (Swiss Water prices) fresh ground in the afternoon and have 2-3 caf cups in the morning. Redber had a wide selection and several roast levels.
No caffeine after noon. I use a 2-cup espresso Bialetti stove top, the second smallest.
Wow, I had never heard of this before. The chemical process for decaf had always put me off before.
From their website: [0]
> When you see the Swiss Water® name, it means your favorite roaster offers 100% chemical-free decaffeinated coffee.
You may have just convinced me to switch to decaf...
[0] https://www.swisswater.com