The solution to cities’ water problems has been hiding in rural areas this whole time

https://qz.com/1396288/the-solution-to-cities-water-problems-has-been-hiding-in-rural-areas-this-whole-time/

When the ancient Romans built their first aqueduct, they set into motion an enduring idea: A modern city needs to build infrastructure that pumps water over, through, and around mountain ranges. Most of today’s cities route this water through massive treatment plants before distributing it to our homes through a maze of underground pipes. When we’re done using it, we pipe wastewater to treatment plants that release so much liquid into our rivers that treated sewage frequently accounts for the majority of the flow.