Perhaps for Coleridge’s Ancient Mariner, “stuck, without breath nor motion, idle as a painted ship upon a painted ocean,” but when thinking about how much potable water the Earth actually contains, it may seem like it’s everywhere (particularly on those interminably rainy spring days), but when actually quantified, it turns out there’s not as much as we may think. [caption id="attachment_9337" align="alignleft" width="300" caption="Illustration by Jack Cook, Woods Hole Oceanographic Institution, © Howard Perlman, USGS"][/caption] This picture, from the U.S. Geological Survey, illustrates the amount of all the Earth’s water as a sphere in relation to the size of the Earth. Thus, all the water on Earth—in the oceans, seas, ice caps, lakes and rivers, as well as groundwater, atmospheric water, and even the water in all the plants and animals—would occupy a sphere with a diameter of about 860 miles, reaching from about Salt Lake City, Utah, to Topeka, Kansas, and having a volume of about 332,500,000 cubic miles. That’s a lot of water—but 96% of it is salt water. Oh, and of the Earth’s freshwater, more than 68% of it is trapped in icecaps and glaciers, and 30% of it is in the ground. So of the meager amount that’s left, that’s what we use for watering our lawns, filling our pools, making beverages and criminally priced spring water, and all the other everyday uses of water. Now, that’s still a lot of water—which is good because that’s all there is. Anyway, it’s something to consider when we think about aspects of sustainability we might not have considered before.