The king's "doctors" in medieval times were little more than witch doctors.

> Clean water depends on how you define "clean"

Always, back to arguing about the definitions of words. Let's put it simply. People before 1800 had little idea about clean water. They didn't know what bacteria was. They didn't know about contaminants. They had very poor sanitation practices. They died of cholera regularly.

Probably the greatest advance in health care in history was the introduction of a clean water supply.

So if you want to quibble about what "clean" means, I'll take municipal water, water filters, and boiling any day over what anybody in medieval times drank. If you don't think your water is clean enough, get a water filter from Amazon. They're cheap, and they work.

In the US, emergency rooms cannot turn away anyone. The care delivered there is light years ahead of anything any king got in medieval times.