Apologies if this has been brought up before, but 'water' and 'well' are too common for search to bring up any results.
Currently, it's impossible to test the quality of land-based water nodes without having to build a well and fill a bucket. While you can attempt to determine the relative location of a node by taking water samples from nearby rivers with a kuksa or a waterflask, this isn't quite so feasible when you're far inland from any lakes or rivers. Having to build and abandon an entire well just to check if the local water is any good just seems a bit much. Perhaps once springwater has been located, a player could take a maximum of, say, 0.1 liters from it for the sake of 'sampling' the water?