"They are applicable everywhere and at every time in the sense of being universal,[1] and they are egalitarian in the sense of being the same for everyone."
Government's in the Middle Ages weren't violating people's rights because they didn't have clean drinking water. They were violating peoples rights in other ways. Governments in sub-Saharan Africa aren't necessarily violating peoples rights because people don't have clean drinking water. Access to clean drinking water varies by time and location, hence, it can't be a human right.
It is universal because everyone, everywhere needs it to survive as much as anyone. Its It's referring to the right, not the resource.
People can survive without clean water. Been doing it for thousands of years ---
A good man would prefer to be defeated than to defeat injustice by evil means - Sallust