An article by:

Philipp Nußbaum

Release date:


8:05 am

One bathtub in a swimming pool

Whereas water on this planet may seem abundant, most is not immediately accessible for human use: In 1993, hydrologist Igor Shiklomanov famously estimated that of all water on earth – representing a volume of circa 1.386 billion km3 – merely 2.5% is freshwater. Let’s take that to a more comprehensible level: If a standard-size water bottle could hold all water in the hydrosphere, all you were able to drink would be a fifth of the amount that fits into the bottle’s cap.

Unfortunately, it doesn’t stop there: 68.7% of all freshwater (the tiny amount of water in the cap) is “locked away” in polar and mountainous regions; another 30.2% is groundwater. Freshwater lakes and rivers like the Tennessee River contain just 0.3% of global freshwater resources – or 0.007% of all water on earth. That’s about enough to fill a single bathtub with water from an Olympic-size swimming pool.

It is no surprise then that the 2030 Water Resources Group (an organization working to help countries achieve water security by 2030) projects global water requirements in 2030 to exceed reliably accessible resources by 40%. Global demand is rising, and it is rising rapidly: Within the next 13 years, the United Nations have estimated that the world’s population will grow from currently 7.5 to 8.5 billion. Already, two out of three people experience water scarcity for at least one month every year. And of course, the total amount of water on earth won’t change; all we have has been recycled for billions of years. Essentially, responsible water use is becoming increasingly important. To better understand how we can conserve water, let’s take a look at how much water we actually use and for what purposes:

The U.S. Geological Survey estimates that the average American uses 80-100 gallons of water per day. In fact, per capita water use in the United States is higher than in any other country – in the United Kingdom, for example, the average citizen uses a quarter of what we use in the U.S. A bath requires 36 gallons, a shower up to 5 gallons per minute. Surprisingly, the most significant contribution comes from flushing the toilet (3 gallons every single time). Many local governments now require faucets, toilets, and showers to use not more than a certain amount of water – meaning the most efficient approach to water conservation is often the adoption of better technology. Try the Environmental Protection Agency’s WaterSense calculator; it will give you an idea of how much water, electricity, greenhouse gas emissions, and money you can save by installing a low-flush toilet.

Of course, domestic water use only constitutes a small part of all freshwater withdrawals in the U.S. (we use most freshwater to produce electricity and for agricultural irrigation). Still, reducing water use and, most importantly, preventing water waste at your home is the most effective way you can contribute to address water scarcity in your community.

Finally, while conserving all the water we can spare is critically important, so is every individual action that could impact a waterway. Conserve what we have, but also protect what we have. There are many ways you can help to safeguard the rivers, lakes, and streams near you; five simple strategies are listed here.