Considering some of the sketchy and very questionable public drinking fountains I used as a kid in the 1970s, that’s probably the source of why I almost never get sick.
As a kid I routinely drank from garden hoses. We all did.
The drinking fountains when we were kids were usually warm too . . . kind of nasty, but it was there and free. Nobody carried water bottles. When you got thirsty, you found a drinking fountain. There was at least one on the side of every school building, generally near the playground or athletic fields. Now the schools have refill stations, but I think they’re all indoors. They would be so easily vandalized. Nobody bothered drinking fountains unless you were in a really rough part of town. We really were fortunate in being able to climb around on monkey bars, get dirty, play outside for hours, ride our bikes and generally act like kids. Summer was for kicking off shoes and playing outside. You never heard of serious viruses in the summer. In the winter there were outbreaks of this and that - chicken pox, measles, German measles . . . back before vaccines for all that. We survived. I never knew anyone to have severe problems. My dad lost a classmate to diphtheria, but that was in the 1920’s.