Hmmmm. I wonder what types of bacteria were found in the fountain sample(s).....and whether they contained a minute amount of harmful bacteria or a large amount of harmless bacteria.

....maybe the toilet water didn;t show any bacteria because they had just been cleaned. As the article said, the terlets are cleansed with chemicals.

I'm just thinking here........

Maybe one more sample-set was needed to help validate the comparison. That being a swab or two from the inside of a student volunteer's mouth. (preferrably a student who had not drunk water from either of the other sample sources).