Most municipalities in industrialized countries regularly publish water quality tests and reports. Most areas also have independent testing labs that are used by private citizens to test their well water, so you're always free to double-check the official reports.
Rural areas are the ones who often don't. And industrial farming isn't the only way (literal) shit can contaminate your water supply.
Well yes, that's why I mentioned reports in the first place.
> And industrial farming isn't the only way (literal) shit can contaminate your water supply.
Agreed. Don't drink water out of fresh looking mountain streams unless you want to risk being sick for weeks.
But the topic is tap water & bottled water. In rural areas in developed countries and where there is little risk of industrial farming contamination, there should be no hesitation in drinking the tap water as a visitor. If you live there, then of course get the water tested. Trusting any water long term without tests is a risk. And since lots of testing is either free or very cheap, there is no reason not to.