When I was a child rivers were so polluted that no one would notice. Also, [Philadelphia rescinds bottled-water alert after chemical spill in the Delaware River](https://www.yahoo.com/entertainment/philadelphia-officials-alert-residents-drink-213744206.html). The article describes how inspectors flew over the spill in a helicopter. Since they could no longer see the spill they declared the water safe to drink. No, I do not believe them either.