A public website both provides the installation's water data and explains its meaning to relative newcomers.

It's a commentary on the environment, but a "positive" one. The creators see it as a marker of the progress made in boosting water quality since 1972's Clean Water Act. It's also a reminder that water is a shared resource, and indirectly a criticism of those who would seek to undo water quality regulations.

You'll find the art project at the Seaport District at Pier 17 in lower Manhattan, although you don't have to travel across town just to see it. You can see it from the bridges linking Brooklyn and Manhattan as well as the Brooklyn waterfront. It'll only be in action until January 3rd, 2020, so you'll have to move quickly if you want a look. This isn't the end, though. It's part of a larger effort to create a self-filtering pool in the East River, and it's easy to imagine systems like this providing at-a-glance water quality elsewhere.