Water conservation

DEFINITION: Management of water consumption in ways that minimize waste, maximize efficiency, and help to maintain adequate supplies of high-quality water

Water conservation is a comparatively simple and inexpensive means of addressing water shortages and making the most of existing water supplies. Effective conservation programs can postpone or prevent the need to construct additional water-supply infrastructure and can also reduce wastewater discharges. As the global population increases, conservation measures become an increasingly important tool for meeting society’s water needs.

In late 2022, the world population reached 8 billion. The United Nations predicted that the population between 2022 and 2050 would grow to 11.2 billion. Because drinking water is a basic human necessity, it follows that the amount of water needed for human existence will increase by a factor of roughly 1.4 over this forty-year period. While such an expansion in water supply is theoretically possible to achieve, the likelihood that it can or will happen is low for several reasons. First, although there is enough water available globally, it is not uniformly distributed around the world when and where it is needed. Second, the costs involved in such an expansion would be astronomical. Third, even if all needed moneys were readily available, it would be difficult to build the necessary facilities and have them operational by the time they would be needed.

Domestic, Industrial, and Agricultural Measures

The greatest potential for water conservation in residential settings is in bathrooms, where more than 45 percent of American home water use occurred in 2020. Traditional toilets, primarily manufactured and installed before the 2010s, used 19 to 26 liters (5 to 7 gallons) per flush. Though these toilets began to slowly be phased out of US manufacturing in the late 2020s, many of these inefficient toilets were still in use. However, low-flow toilets using 13 or fewer liters (3.5 gallons) per flush—and ultra-low-flush models using as little as 6.1 liters (1.6 gallons)—began increasingly being installed in new homes and as replacements for traditional toilets in older homes in the late 2010s. Baths and showers also use large amounts of water, and low-flow showerheads can contribute to water conservation efforts.

A great deal of water is also wasted in kitchens. Water can be conserved at kitchen sinks through simple means, such as collecting food scraps for compost piles rather than putting them in garbage disposals. Low-flow sink faucets are also available. Running automatic dishwashers only for full loads is another water conservation technique; the same is true for clothes washers. Older models of both types of washers can be replaced with newer, more water-efficient models, which can save households 8,000 to 11,000 gallons each year.

Another potential source of water conservation in residential areas is found outside the homes, in plant and lawn watering. Methods of saving water include decreasing lawn sizes, landscaping with plants that require low amounts of water (known as xeriscaping), mulching to reduce moisture evaporation from the soil, minimizing the frequency of watering, and using drip systems instead of sprinklers.

Business and industrial settings use copious amounts of water. In some cases, water conservation measures may involve simple changes in the way things are done, such as substituting sweeping for the washing down of floors. In most cases, however, in these settings, water conservation on a noticeable scale results from process changes of some type. For example, by converting from a water-cooled ice machine to an air-cooled one, a restaurant may improve water efficiency in its ice making by 25 to 50 percent.

The largest amounts of water, around 70 percent by most estimations in the mid-2020s, are used in agriculture for irrigation. In the United States, a history of relatively cheap and readily available water led farmers to waste great amounts through improper or excessive application. Water can be and has been saved through computerized timing of water application. Modifications of irrigation procedures have also helped. For example, drip irrigation, which applies water slowly and uniformly at or below soil level adjacent to plants through mechanical water outlets, has produced significant water savings over traditional methods of simply spraying water onto the soil.

Other Ways of Conserving

As is true of the consumption of other commodities, water usage can be affected by pricing. Water-conserving rates exhibit increasing unit costs as volume used increases. One simple model determines a certain rate for the average amount of water a household might be expected to use and a much higher rate for all water used over that average amount.

Yet another way in which municipalities, as well as home and business owners, can conserve water is by finding and repairing leaks that occur anywhere in water distribution systems; water audits—careful reviews of water usage over time—can help to identify leaks. In some water distribution systems, documented leakages have been found to amount to losses of more than 50 percent of the water sent through the systems. In 2023, the Environmental Protection Agency (EPA) reported that household leaks account for nearly 10,000 gallons annually.

Water reuse may be thought of as another form of water conservation. Ample opportunities for water reuse exist during industrial processes. For example, wastewaters that were being treated on-site and discharged into receiving streams might be reused as cooling water. Households might recycle water used for dishwashing or bathing as irrigation water for outdoor plants. While it is possible to treat sewage for reuse by households, most people are not yet ready to accept such a conservation measure.

The negative aspects of water conservation are generally related to monetary issues. For example, successful water conservation efforts can lead to reduced revenues for water utility companies, which may then be forced to increase their rates. Conserving water over the long term may also reduce the “slack” in the system, making short-term drought savings difficult to achieve and reducing the amount of water available for water rationing. Some water conservation efforts can be expensive to put in motion, while the actual savings from reduced water use are achieved more slowly, over a period of time. Such water conservation is not always cost-effective.

Bibliography

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