Grab a clear glass bottle—the simpler, the better. Fill it with your suspect water (tap, pond, or even your fancy bottled stuff). Now, hold it up to a bright light and squint. Do you see any weird floating specks? Probably not. That’s okay. This test is mostly for dramatic effect.
I once did this at a dinner party. I stared at a glass of sparkling water for five minutes. My friend thought I was having a stroke. I wasn’t. I was just hunting.
