Without water filtration, well, you'd probably be dead. That's it. OK, maybe there is a little more to it. We've explored the history of water filtration, going back as far as 4,000 years, all the way up to modern methods such as activated carbon, resin filters, and reverse osmosis. YES! Even reverse osmosis, whatever that is. Learn how water filtration began, how the processes work and evolved, and why we still have water shortages even though most of the planet is covered in water.