Water covers 71% of the Earth’s surface, but good ol’ H2O is a much more precious resource than it appears. Less than 0.8% of Earth’s water is freshwater in lakes, rivers, or underground aquifers. And much of that already tiny fraction has been rendered unusable by pollution or is lost to poor management and inefficient agricultural practices. What’s worse, climate change and overexploitation of existing water resources mean that communities from California to Cambodia are struggling to provide safe water at an affordable price.