After hearing many sources (news reports, articles, everyday conversations, etc.) use the term "agua potable" when they really just mean "tap water that you still can't drink" I told someone to look up "agua potable" in the dictionary. And lo and behold.. it has become so common to call any type of running water in certain parts of South America "agua potable" that the RAE itself has a second definition of the term which just means that it's water that is acceptable or "pasable". Several native speakers in Lima, Peru confirm that such descriptions as "pasable" and "aceptable" do not to them denote that the water is drinkable, just that they can bathe with it which fits their understanding of "agua potable" as well. So I guess the term actually is accurate.
For me this was an eye opener. In English potable definitely always means "drinkable" and it seems to have come from the latin "potare" where it meant to drink as well. The "pasable" definition also mentions that it's colloquial. I guess my point is that initially at least it seems that they kept repeating inaccurate information calling water potable because that's what other countries had. Perhaps eventually it became so common to use the term this way that even the RAE then amended the definition to match the new reality with the consequence that now one cannot depend on the term meaning anything about the drinkability of the water (possibly dangerous in translation situations).
I am kind of just guessing here with this last theory, so my question is: Is there more to this story or am I misunderstanding what this term has traditionally meant in South America?
As an aside, is there any way to tell when the RAE may have added to or altered their definition of a given word / term?
- RAE definition: http://dle.rae.es/srv/search?m=30&w=potable
- Example of prominent news report using the term "agua potable" for water you still shouldn't drink without further cleansing: http://elcomercio.pe/peru/apurimac/dia-mundial-agua-potable-agua-cano-174852
- As mentioned below, another news report: https://peru21.pe/lima/arequipa-agua-potable-apta-consumo-humano-186878
Update: Just wanted to add a piece of the SEDAPAL bill (Servicio de Agua Potable y Alcantarillado de Lima). First of all, "agua potable" is part of their name, and second, what they charge you for (tap water, shower water, etc, not bottled water) is clearly called "agua potable": https://imgur.com/a/F9oVy
So for Peru we can clearly see why tap water is known as "potable water". So now just ask someone from Peru if you can drink straight tap water. They will overwhelmingly say that that would not be a good idea. A SEDAPAL employee doing an inspection also told me no, trying to discuss the meaning of the term "potable water" with him went nowhere.