When you turn on the kitchen tap and fill up a glass of water, you probably don't think twice about it. But did you know more than one billion people lack access to a safe supply of drinking water? And by 2025, it's projected that half of the world's population will live in a water-scarce region if today's trends continue. Gulp! One more scary fact: Currently, water-related diseases are the leading cause of death in the world. Here's what you need to know about H2O.

Where that water in your glass comes from
340 billion gallons of fresh water are pulled from rivers, streams and reservoirs every day in the U.S. and cleaned for residential, commercial and industrial uses. That's more than five gallons of water for every person in the world each day.

We're draining our supply
We waste a lot of clean water unnecessarily. The average household uses 350 gallons of water per day. That's enough to fill almost 100 bathtubs. (We're all for staying clean, but that's a lot of baths for one day!) Most household water is used for bathing and for flushing toilets, and an average 15 percent is lost to leaks. Every day, five billion gallons of drinkable water is used to flush toilets in the U.S. Outside the home, your lawn is the thirstiest culprit of all and can be a major drain on our fresh water resources. In states such as California, lawn care accounts for half of a household's water usage.

All dried up
Droughts deplete topsoil and lower agricultural output, and ironically enough, dry soil cannot absorb and hold water as well as topsoil, so once we're in a drought, it's tough to get out! Combat drought in your plot of land by using mulch to retain soil moisture.

Good enough to drink?
Probably not. And you might not want to swim in there either. Fresh water bodies are polluted by storm-water runoff from construction sites, impervious surfaces like pavement and by industry processes that cast off wastewater from cooling and other manufacturing processes that can contain toxic chemicals. To top it off, agricultural runoff of fertilizer and pesticides along with poorly treated "organic wastes" or sewage eventually end up in the water system — yuck. Pollution can degrade water to make it unsafe for recreation.

Water pollution
Water pollution is a problem for our health and for the natural world. We've been cautioned to avoid certain types of fish and seafood because of their high mercury content. How did it get there? Industrial processes and coal-fired power plants release tons of mercury into the air, and when it rains, that mercury ends up in our water and the bodies of many organisms. It travels up the food chain and reaches our mouths in tuna fish sandwiches or other tasty treats.

From the global to local stage, many water-concerned groups are committed to making a difference and are working to clean up our act. Conservation efforts abound, but we can all do our part to conserve water in our homes.