More than two-thirds of the earth’s surface is covered with water, but most of it is useless for healthy human hydration. Excluding seawater, glaciers and polar ice caps, less than 1 percent of the planet’s life-sustaining water is in lakes, rivers, streams and underground aquifers. Much of that readily available drinking water requires treatment to eradicate harmful microbes and toxins. As a result, access to clean drinking water is limited and precarious for many of the