The data source selected and considered for the submission seems to be the best one for this theme, indeed.
Just for completeness sake, I’d like to add that the Ministry of Health offers another dataset in CSV format that includes fecal coliform aggregate data (percentages). However, it is not detailed by water source.
As for the open license, it is important to note also that this kind of data (sensor / exam readings) is not copyrightable in Brazilian copyright law as it cannot be considered an “intellectual creation”.
It appears that the resource has been changed since I first posted, but you’ve found it. I would edit my original post to correct the link, but it seems like the forum doesn’t let me do it so many months later.