Water conservation helps manage fresh water wisely, protects water in the environment, and meets the needs of people today and in the future. It helps prevent water shortages. It includes all rules, plans, and actions needed to achieve these goals. Factors like population size, household size, growth, and higher income influence how much water is used.

Even though the terms "water efficiency" and "water conservation" are sometimes used the same way, they are different. Water efficiency involves improvements, such as new technology, that help use water more effectively. Water conservation refers to the act of saving or preserving water. In short, water efficiency focuses on developing tools and methods to use water better, while water conservation is about reducing water use or protecting it.

Climate change and other issues have increased stress on natural water sources. This is especially true in industries and farming, where water is used for irrigation. Many countries have created policies to help conserve water. Key steps to conserve water include reducing unnecessary water loss, waste, and use. Another step is avoiding actions that harm water quality. A third step is improving how water is managed to use it more wisely or increase its helpful use.

Solutions using technology are available for homes, businesses, and farms to reduce water use or loss. Water conservation efforts that involve communities are often started at the local level by city water services or regional governments.

Aims in water efficiency

Water conservation is the practice of using water wisely. Although people had been trying to conserve water, it became more common because of several reasons. These reasons include limited water supplies, rising costs for building water systems, laws from state and federal governments, people wanting to protect the environment, and the fact that saving water no longer leads to more money. Most people focus on limited water supplies because water is supposed to be a renewable resource, but it is not always available in enough amounts.

Strategies

Water conservation strategies share common goals, such as reducing water loss and waste, protecting water quality, and improving how water is managed to use it wisely. One method is rainwater harvesting, which involves building ponds, lakes, and canals, expanding water reservoirs, and installing gutters and filters on homes to collect and store rainwater. In many places, people use clean containers to collect rainwater, boil it for drinking, and provide it to those in need. Collected and filtered rainwater can also be used for flushing toilets, watering gardens, and irrigation for small farms.

Protecting groundwater is another important strategy. When it rains, some water soaks into the ground and becomes groundwater, stored in underground layers. Contamination from sources like leaking fuel tanks, septic systems, landfills, chemicals, and road salt makes groundwater unsafe for drinking and slows its natural recovery. Preventing pollution helps keep groundwater clean and available for future use.

Using groundwater wisely is also key. Groundwater flows underground and eventually reaches rivers and streams. Too much pumping can lower groundwater levels, deplete the resource, and harm surface water supplies like lakes and rivers. In coastal areas, overuse can cause saltwater to seep into groundwater, polluting it. Using groundwater sustainably helps avoid these problems.

Teaching people about water management is a vital part of conservation. Sharing knowledge about water systems with farmers, policymakers, and the public helps create effective plans to protect water resources.

Conserving water is essential for wildlife. Many animals in temperate areas depend on water, and freshwater species are harmed by pollution, which disrupts their habitats.

World Water Day is observed on March 22.

Social solutions

Water conservation programs often start at the local level, led by city water services or regional governments. Common methods include public education, higher water prices for heavy users, and rules limiting outdoor water use like watering lawns or washing cars. In dry areas, cities may require homes to use landscaping that needs less water, such as xeriscaping. In California, most outdoor water use comes from homes, so outreach to both families and businesses is important.

A key goal of water conservation is to install water meters in all homes. However, not all homes have meters. In the UK, fewer than 30% of homes are metered. In the US, meters can reduce water use by 20-40%. Meters help people track their water use and find leaks. They also give people a reason to save water to save money.

Some experts say farmers should be a focus of conservation because farming uses about 70% of the world’s fresh water. Many countries give farmers money to help them grow crops, but this can lead to waste. Conservation groups suggest removing these subsidies to encourage farmers to use water more efficiently.

New technology offers ways to save water. For example, toilets now have options like full or half flushes to use less water. Water can also be used in stages, such as using it for tasks before it needs to be cleaned again. Some homes, like Earthships, use these methods. Modern showerheads use less water than older models, and some systems recycle shower water with pumps and filters. These systems are used in places like the VIRTUe LINQ house and also reuse heat from the water.

Studies show that replacing old toilets and washing machines is more effective for saving water than just using less water in daily activities. Other home water-saving tools include efficient showerheads, composting toilets, faucets with aerators, rainwater collection, smart irrigation systems, garden hose nozzles, and automatic faucets.

Smart water meters can help homes save water by showing users how much they use and offering tips to reduce it. A study in Spain found that homes with smart meters saved more water. These meters also give rewards for saving water.

Water-saving tools used in homes can also help businesses. Examples include waterless urinals, car washes that don’t use water, foot-operated taps, and systems that use water more efficiently. Infrared taps save water by using short bursts for cleaning.

Messages reminding people to save water can be effective. A 2014 study showed people are more likely to save water after seeing such messages. A 2016 survey found that education about water use influences people’s willingness to conserve it.

Industries and businesses use a lot of water. In rich countries, about 59% of water is used for industry, while in poorer countries, it’s about 8%. Companies can save water by fixing leaks, creating water-saving plans, and checking systems regularly. Installing rain sensors to stop irrigation during rain is another way to save water.

Water is important for farming. Plants use a lot of groundwater, so it needs to be replaced. In agriculture, water is divided into blue water (water above and below ground) and green water (water used by plants from rain). Only blue water is measured as a resource.

For farming, using water efficiently means reducing waste from evaporation, runoff, or drainage while growing crops. Tools like evaporation pans and crop-specific calculations help determine how much water plants need. Flood irrigation is old and uneven, while overhead systems spread water more evenly. Drip irrigation is the most efficient but expensive method. It can save up to 30,000 gallons of water yearly. Cheaper methods, like soaking hoses, also help reduce water waste.

Problems

A survey from 2014 showed that many people were unlikely to use recycled water for drinking because of fear. However, people who knew more about saving water were more likely to say they would use recycled water. A later survey in 2021 found that some people avoided choosing an option because they were worried about getting sick. Researchers think these people picked the neutral choice to still support an environmentally friendly action.

Wasting water is the opposite of saving water. In homes, it means letting water flow without a useful purpose. Using water inefficiently is also considered wasteful. According to the EPA, leaks in American homes can waste about 900 billion gallons of water each year. Water management groups often avoid giving clear definitions for water waste because the idea is vague.

Definitions of water waste are usually found in local laws during droughts. For example, some rules describe wasting water as letting water leak or flow into gutters, sewers, or nearby areas from taps, sprinklers, or pools. These rules also say that using more water than needed to clean something, like a car or sidewalk, counts as waste.

Water companies and other groups often list examples of wasteful water use and rules against it. Cities like San Antonio, Texas, Las Vegas, Nevada, and San Diego, California, have such lists. Palo Alto, California, has permanent rules against wasting water, such as fixing leaks, avoiding irrigation after rain, and using non-drinking water when possible. Similar rules exist in Victoria, Australia. In England, Scotland, Wales, and Northern Ireland, temporary bans on using water for things like washing cars (called "hosepipe bans") are sometimes used.

Strictly speaking, water that goes into sewers or the environment is not truly wasted because it returns to the water cycle through rain. However, if the water comes from a faraway place or a different area, it can harm the environment. What is "wasted" is the water that was collected, treated, and transported to be used. Using water efficiently saves money and helps keep more fresh water in lakes, rivers, and underground sources for others and ecosystems. For example, flushing items like cigarette butts or tissues down the toilet wastes water because it cannot be reused.

A related idea is "water-use efficiency." Water use is inefficient if the same task can be done with less water. Technical efficiency compares how much water is used for a task, like how a more efficient showerhead uses less water. However, technical efficiency alone does not help decide if investing in water-saving measures is worth the cost unless the value of water and savings are measured. This idea, called economic efficiency, is part of water conservation efforts.