I never suggested "causality", I simply noted the "correlation" which is useful because they can indicate a predictive relationship that can be exploited in practice.

Correlation is the starting point, without correlations you could never determine causation.

To state as you did that correlation "Never has, never will" prove causation is also a fallacy. You need to reread the wiki on "Correlation does not imply causation".

As to the question, we don't have any compiled records or sufficient records to make a determination. What we can see based on records from the last couple years is 3rd world countries without water chlorination have significantly lower instances of colon cancer.