In August, Toledo residents woke up to warnings that they shouldn’t drink the water coming out of their tap. A toxin was in the water, the result of an algal bloom in Lake Erie.

In the days after the incident, I started talking with my editor at Science News for Students about how Toledo was just one in a series of incidents around the country that had left people without clean water. I ended up writing a feature, “Will water woes leave Americans thirsty?,” that tried to tally up some of those incidents, as well as longer-standing problems and what, if anything, is being done to address them.