All the water
It’s not just electricity that Niagara Falls provides for the local community, and those a bit farther afield. About 20% of the US drinking water makes the vertigo-inducing journey over the edge of the Falls. So you might even have had some of that water in your tea!
If you’re visiting, it’s not a good idea to dip your cup in and quench your thirst. The water has to go through at least one of the several treatment plants along the edge of the riverbanks before it makes its way into your home and comes running out of your tap.