In 2015, approximately 11000 people got sick in Dejvice, Prague 6, after wastewater contaminated the fresh water supply[1]. I was out of town, but when I returned in 2016/2017, the incident was still fresh in people's memories and their water consumption patterns clearly changed in favour of bottled water.

[1]: https://vodnihospodarstvi.cz/dejvicka-havarie-a-epidemie-neb...