Drought is pushing saltwater up the Delaware River—Philadelphia’s drinking water source

The Delaware River provides drinking water for some 14 million people, including most of Philadelphia but also New Jersey and New York.

Salty oceanwater is creeping up the Delaware River, the source for much of the drinking water for Philadelphia and millions of others, brought on by drought conditions and sea level rise, and prompting officials to tap reservoirs to push the unpotable tide back downstream.