A slow, methodical transformation of the $400-billion-a-year water-management industry is currently in progress, and nanotechnology appears to be leading the way.

The promise of nanofiltration devices that “clean” polluted water, sifting out bacteria, viruses, heavy metals and organic material, is driving companies like Argonide and KX Industries, which developed technology used in Brita filters, to make nanotechnology-based filters for consumers. Two products incorporating nanotechnology are going to hit the market within the next year and are already being tested in developing nations.