How to Desalinate Water: A Guide for Home Use

Water is essential for life, but not all water is safe or suitable for human consumption. According to the United Nations, more than 2 billion people lack access to safely managed drinking water services, and about 1.5 billion people face water scarcity12

One possible solution to this problem is desalination, which is the process of removing salt and other minerals from saline water, such as seawater or brackish water, to make it fresh and potable. Desalination can provide a source of freshwater in areas where freshwater is scarce or contaminated, such as arid and coastal regions, islands, or ships. Desalination can also reduce the pressure on existing freshwater resources and help prevent water conflicts.

However, desalination is not a simple or cheap process. It requires a lot of energy, infrastructure, and technology, which can be expensive and environmentally harmful. Desalination also produces a large amount of brine, which is the concentrated saltwater that remains after the freshwater is extracted. Brine can have negative impacts on the marine ecosystem if not properly disposed of or reused34

Therefore, desalination is not a perfect or universal solution to the global water crisis, but it can be a valuable option in some situations. In this article, we will explain what desalination is, why you should do it, how you can do it at home, and what are the benefits and challenges of doing so.

What is desalination?

Desalination is the process of removing salt and other dissolved solids from saline water to make it fresh and drinkable. Saline water can be seawater, which has an average salinity of about 35 grams of salt per liter of water, or brackish water, which has a lower salinity than seawater but higher than freshwater5

There are different methods of desalination, but the most common ones are distillation and reverse osmosis. Distillation involves heating saline water until it evaporates, leaving behind the salt and other impurities. The vapor is then condensed into freshwater. Reverse osmosis involves forcing saline water through a semipermeable membrane that allows water molecules to pass through but blocks salt and other contaminants. The freshwater is collected on one side of the membrane, while the concentrated brine is discharged on the other side6

Both methods require a lot of energy to operate, which can be derived from fossil fuels, renewable sources, or waste heat. Both methods also produce a large amount of brine, which can be treated, reused, or disposed of in various ways. Some examples of brine reuse are irrigation, aquaculture, salt production, or power generation. Some examples of brine disposal are deep well injection, evaporation ponds, or ocean outfalls7

Why should you desalinate water?

Desalinating water can provide several benefits for human health and well-being, especially in areas where freshwater is limited or polluted. Some of these benefits are:

• Desalinating water can provide a reliable and safe supply of drinking water that meets the World Health Organization (WHO) quality standards. Drinking contaminated water can cause diseases such as diarrhea, cholera, typhoid, dysentery, hepatitis A, and polio. Desalinating water can prevent these diseases and improve public health8
• Desalinating water can also provide water for other domestic uses such as cooking, washing, cleaning, and sanitation. Having access to adequate and clean water can improve hygiene and dignity for people who lack basic services such as toilets or showers.
• Desalinating water can also provide water for agricultural uses such as irrigation or livestock watering. Agriculture accounts for about 70% of global freshwater withdrawals and is one of the main drivers of water scarcity. Desalinating water can increase food production and security for people who depend on farming for their livelihoods.
• Desalinating water can also provide water for industrial uses such as manufacturing or cooling. Industry accounts for about 20% of global freshwater withdrawals and is another major driver of water scarcity. Desalinating water can support economic development and growth for people who work in various sectors.
• Desalinating water can also provide water for environmental uses such as wetland restoration or wildlife conservation. Wetlands are ecosystems that provide many benefits such as biodiversity, flood control, carbon sequestration, and tourism. Wildlife are animals that depend on natural habitats for their survival. Desalinating water can protect and enhance these natural resources for people who value them.

How can you desalinate water at home?

Desalinating water at home may seem like a daunting task, but it is actually possible with some simple materials and methods that you can find or make yourself. Here are some examples of how you can desalinate water at home:

• Solar still: A solar still is a device that uses the sun’s energy to distill water. You will need a large bowl, a cup, some plastic wrap, and a small weight. You will also need some salt water, which you can either collect from the ocean or make yourself by adding salt to tap water. To make a solar still, follow these steps: 9
  • Pour the salt water into the bowl until it is about 1 inch deep.
  • Place the cup in the center of the bowl, making sure it does not touch the salt water.
  • Cover the bowl with plastic wrap, stretching it tightly over the rim of the bowl.
  • Place the weight on top of the plastic wrap, above the cup.
  • Place the bowl in a sunny spot, such as a window sill or a garden.
  • Wait for several hours or until you see water droplets forming on the plastic wrap.
  • The water droplets will slide down the plastic wrap and fall into the cup, leaving behind the salt and other impurities in the bowl.
  • Collect the freshwater from the cup and enjoy.
• Pot and lid: A pot and lid is another device that uses heat to distill water. You will need a pot with a lid, a smaller pot or bowl that fits inside the larger pot, and some ice cubes. You will also need some salt water, which you can either collect from the ocean or make yourself by adding salt to tap water. To make a pot and lid still, follow these steps: 10
  • Pour the salt water into the larger pot until it is about half full.
  • Place the smaller pot or bowl inside the larger pot, making sure it does not touch the salt water.
  • Cover the larger pot with the lid, turning it upside down so that the handle points down.
  • Place some ice cubes on top of the lid, around the handle.
  • Place the pot on a stove and bring the salt water to a boil.
  • Wait for several minutes or until you see steam rising from the salt water.
  • The steam will condense on the lid and drip down to the handle, where it will fall into the smaller pot or bowl, leaving behind the salt and other impurities in the larger pot.
  • Turn off the stove and carefully remove the lid and the smaller pot or bowl from the larger pot. Collect the freshwater from the smaller pot or bowl and enjoy.

Membrane filter: A membrane filter is a device that uses pressure to reverse osmosis water. You will need a membrane filter, which you can buy online or at a hardware store, two plastic bottles, some tubing, and a hand pump. You will also need some salt water, which you can either collect from the ocean or make yourself by adding salt to tap water. To make a membrane filter still, follow these steps: 11

• Cut off the bottoms of both plastic bottles and discard them.
• Attach one end of a tube to the membrane filter and insert it into one of the bottles through the neck.
• Attach another tube to the other end of the membrane filter and insert it into another bottle through the neck.
• Fill one bottle with salt water and attach it to the hand pump.
• Squeeze the hand pump to create pressure and force the salt water through the membrane filter.
• Wait for several minutes or until you see freshwater coming out of the other bottle, leaving behind the salt and other impurities in the first bottle.
• Detach the bottles from the tubes and the pump.
• Collect the freshwater from the second bottle and enjoy.

What are the benefits and challenges of desalinating water at home?

Desalinating water at home can have some advantages and disadvantages compared to using conventional sources of freshwater, such as tap water, bottled water, or rainwater. Some of these are:

Benefits:

• Desalinating water at home can provide you with a self-reliant and independent source of freshwater that does not depend on external factors such as infrastructure, availability, or quality of other water sources. You can desalinate water whenever and wherever you need it, as long as you have access to saline water and some basic materials and methods.  
• Desalinating water at home can also save you money and resources that you would otherwise spend on buying or transporting freshwater from other sources. You can reduce your water bills, avoid plastic waste from bottled water, and lower your carbon footprint from water transportation.
• Desalinating water at home can also give you a sense of satisfaction and achievement that you have created your own freshwater using your own skills and creativity. You can also learn more about the science and technology behind desalination and share your knowledge and experience with others.

Desalinating water at home can also pose some difficulties and risks that you should be aware of and prepared for. Some of these are:

• Desalinating water at home can be time-consuming and labor-intensive, depending on the method and amount of water you want to desalinate. You may need to spend hours or days to collect enough freshwater for your needs, while also maintaining and cleaning your equipment and materials.
• Desalinating water at home can also be inefficient and wasteful, depending on the method and amount of water you want to desalinate. You may need to use a lot of energy, such as electricity, gas, or firewood, to heat or pump the salt water, which can increase your energy bills and environmental impact. You may also produce a lot of brine, which can be harmful to dispose of or reuse if not done properly.
• Desalinating water at home can also be unsafe and unhealthy, depending on the method and quality of water you want to desalinate. You may need to use chemicals, such as bleach or iodine, to disinfect or purify the salt water before or after desalination, which can be toxic or corrosive if not handled carefully. You may also need to test or treat the freshwater after desalination to ensure that it meets the WHO quality standards for drinking water, which can be complex or costly if not done correctly.

Conclusion

Desalination is a process of removing salt and other minerals from saline water to make it fresh and drinkable. Desalination can provide a source of freshwater in areas where freshwater is scarce or contaminated, but it also requires a lot of energy, technology, and infrastructure, which can be expensive and environmentally harmful.

Desalination is not a perfect or universal solution to the global water crisis, but it can be a valuable option in some situations. Desalination can also be done at home with some simple materials and methods that you can find or make yourself.

Desalinating water at home can provide you with a self-reliant and independent source of freshwater that does not depend on external factors. It can also save you money and resources that you would otherwise spend on buying or transporting freshwater from other sources. It can also give you a sense of satisfaction and achievement that you have created your own freshwater using your own skills and creativity.

However, desalinating water at home can also pose some difficulties and risks that you should be aware of and prepared for. It can be time-consuming and labor-intensive, inefficient and wasteful, unsafe and unhealthy, depending on the method and quality of water you want to desalinate.

Therefore, before you decide to desalinate water at home, you should weigh the pros and cons carefully and do your research thoroughly. You should also follow the instructions carefully and take precautions accordingly. You should also consult with experts or authorities if you have any doubts or questions.

Desalinating water at home is not an easy task, but it is possible with some effort and ingenuity. If you are interested in trying it out yourself, we hope this article has given you some useful information and guidance on how to do it safely and effectively.