1. We’re running out of water.

We see it in the headlines almost every day: Drought in Texas and China. Nevada’s Lake Mead in danger of going dry. The Colorado River and the Rio Grande no longer flowing to the sea.

Water seems to be getting more and more scarce. But it’s not. The amount of water on Earth isn’t changing, and as a planet we’re in no danger of running out.

One of the most misleading “facts” we learn about water, starting in the second grade or so, is that 97.5 percent of the water on Earth is unusable by humans, because it’s salty ocean water.

Actually, the oceans are Olympian springs of fresh water — every day, the sun, the sea and evaporation combine to make 45,000 gallons of rainwater for each man, woman and child on Earth. Even in the United States, where we use water with profligacy, the oceans are making more fresh water for each of us in a month than we’ll use in a decade.

And one of the most remarkable qualities of water, of course, is that we never really use it up. Water reemerges from everything we do with it, whether it’s making coffee or making steel, ready to use again.

The problem is that we’ve built our communities, our farms and our reservoirs in places we expect water to be. The scarcity we’re seeing is a result, in part, of a shifting climate — it’s still raining, but it may not be raining in the watersheds of our reservoirs. Water scarcity is also a result of population growth; more people need more water. And it is often a hidden cost of economic development. As people get wealthier, they use more water for things such as bathing and running the dishwasher, and more energy, which requires huge volumes of water.

2. Bottled water is better than tap water.

Tap water in the United States is among the safest in the world. And it is much more closely monitored than bottled water. Cities must test their water every few hours and report any safety issue within 48 hours. Bottled-water companies are required to test their water only once a week, and they are not required to report problems.

Occasionally, there are issues with municipal water in the United States. The presence of lead in some parts of Washington’s water system is a vivid example. But those exceptions underscore how important safe water is and how rare problems are.

Anyone who is worried about safety should use a commercial faucet or pitcher filter. And anyone who thinks tap water tastes bad compared with bottled water should remember that you usually buy bottled water from a cold case, when you’re really thirsty. That’s why it tastes so great. Keep a pitcher or bottle of tap water in your refrigerator, and it will taste just as good as bottled water. In fact, in blind taste tests, people can’t reliably pick bottled from tap.

3. This is going to be a century of water wars.

Although we hear all the time that “water is the next oil” — that it will become a source of international conflict, that its price will soar — there aren’t likely to be water wars anytime soon.

We fight over oil because it is essential. We also fight over it because it is transportable over long distances; there is an elaborate system of pipelines, ships and trucks for moving it wherever it’s needed. If you secure oil in a war, you can actually use it. And there is an economics of oil that supports moving it — and fighting over it.

When oil was cheap — it cost $30 a barrel as recently as 2003 — 10 gallons of crude cost $7. Ten gallons of tap water, meanwhile, costs 3 cents. Water is simply too cheap to fight over, and too hard to move around the world on demand.

Aaron Wolf, a professor at Oregon State University, has looked back more than 1,000 years and has found no instance of armed conflict between countries in which water was a primary issue. Indeed, Wolf’s research shows that when nations sit down to resolve water issues, they often end up resolving wider conflicts.

4. With more people and a growing economy, America is using more water all the time.

Actually, one of America’s greatest conservation stories of recent years is that, as a country, we use less water today than we did in 1980. In that span, the United States has doubled the size of its economy and added 70 million people, yet we use 10 percent less water than we did 30 years ago.

Most of that savings has come from farmers and power plants using less water, while producing dramatically more food and more electricity. Agriculture and electric power generation are the two largest consumers of water each day, accounting for 80 percent of water use.

Of course, this doesn’t mean we can take 20-minute showers or cultivate lush lawns in Phoenix. Even as total water use has fallen, water use at home has risen in the past 30 years, although modestly. The average American in 2005 used about 3.5 gallons more per day than in 1980. That’s one extra toilet flush for each of us.

But municipal water is the most expensive and complicated water to get, deliver and dispose of. The economic vitality of cities requires water pipes, pumps and treatment plants. So for cities, the cheapest water is water that residents don’t use. And conservation liberates existing water for new residents and businesses.

Even small steps add up: not flushing the toilet if you don’t need to, using all those half-empty water bottles to fill the dog bowl, paying close attention to how much water your garden or lawn actually needs.

5. You need to drink eight glasses a day.

Although this bit of health advice has stuck around like a discarded piece of gum, there is no medical basis for it.

For most healthy people, the best signal to drink — water, juice or even caffeinated beverages — is thirst. Our sense of thirst is incredibly alert. It’s triggered if our internal water balance gets just 1 percent out of kilter.

This sense does dim a bit as people age, so for elderly people, consciously drinking several glasses of water, or any other beverage, is a good daily habit.

But to puncture the eight-glasses-a-day myth, all you have to do is try to follow the advice for a couple of days. Most people would have to work hard to gulp down an eight-ounce glass of water once an hour, every hour, from 9 a.m. to 5 p.m. And you’d quickly be reminded what your body does with excess water.


Charles Fishman is the author of “The Big Thirst: The Secret Life and Turbulent Future of Water.” He writes for Fast Company magazine and blogs about water for National Geographic.

Read more from Outlook, friend us on Facebook, and follow us on Twitter.

Water is the most familiar substance in our lives, and the most important. Every cell in our bodies is plumped full of water; every heartbeat, every thought — including thoughts about water — happens only because of the cascade of chemistry that water makes possible. Yet we know almost nothing about water, starting with such basics as: Where does our water come from? Where does it go once it disappears down the drain? In fact, even what we think we know about water is often wrong.