How Does Solar Water Purifier Work?

Updated on October 17, 2022

How Does Solar Water Purifier Work?

How does solar water purification work?

A solar water purifier can work in two ways:

  1. Nullify biological contaminants directly by ultraviolet light
  2. Evaporate and distill water by heat energy, leaving contaminants behind

Water is the source of life. Almost 60% of the human body consists of water and about 70% of Earth’s surface is covered with water. However, this essential element for human existence and the sustainability of our planet is slowly missing in its drinkable form.

The impact of the water crisis is huge, as nowadays:

  • approximately 771 million people are without sufficient access to drinkable water,

  • around 1.7 billion people are without sufficient access to a toilet,

  • almost 1 million people die each year from water deprivation, sanitation and hygiene-related diseases,

  • almost every 2 minutes, somewhere in the distant part of this world a child dies from a water-related disease,

  • $260 billion of losses are incurred due to the lack of clean water and sanitation.

With the ever-growing global population and the advancement of our civilization that needs vast amounts of resources, including water, now more than ever is the time to invest and learn about sustainable ways of procuring drinkable water.

One of the emerging innovations in this field is the solar water purifier.

How To Make Solar Water Purifier (DIY)


How Does Solar Water Filter Work?

A solar filter is the latest innovation that can turn turbid or “unclean” water into water that households can use by relying on solar energy. There are various solutions and innovations in the field of solar filtration worldwide, but the principle is the same.

Solar filter exploits the components of solar energy: the heat, and in some cases also the UV radiation.

For example, Princeton University researchers developed a technology called a Solar Absorber Gel that purifies water using only sunlight. This gel absorbs water and when it is heated, it changes shape and releases the water.

The two other layers of this filter are made of polydopamine (PDA) and alginate. The combined work of those two layers transforms the sun’s energy into heat and filters out metals, pathogens, and other molecules from the turbid water. 

Another example is the Swedish Solvatten, a portable 5-litre container that when placed in direct sunlight, heats the water inside it and exposes it to UV radiation.

This combined effect of heat and UV radiation purifies the water of pathogenic material in 2-6 hours, leaving the concerned household with 5 litres of pure water.

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New innovations using solar filtration

How Does Solar Power Clean Water?

As a non-exhaustive and renewable clean energy resource, there’s hardly a better one to use for water purification than the Sun itself.

As it is noted above, the components of sunlight that can be used for water purification are UV radiation and heat. This method of purification is also called the “SoDis”.

Solar energy is divided into three wavelengths:

  1. UV radiation
  2. infrared radiation (IR) and
  3. visible light.

The effects of UV radiation can be devastating to the human skin and can destroy living cells, but most of it is absorbed by the Earth’s ozone layer.

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Sunlight includes electromagnetic waves at different frequencies – UV is one of them

The UV-A radiation in the wavelength range of 320nm – 400nm can reach the Earth’s surface and when exploited properly, can kill pathogens in water.

UV-A radiation interacts with the DNA, nucleic acids and enzymes of the living cells, and eventually kills the pathogen cells by changing their molecular structure.

Also, UV radiation reacts with oxygen dissolved in the water and produces oxygen free radicals and hydrogen peroxides that are also lethal to pathogens.

Furthermore, the IR from the solar energy produces heat, and heating up the water to 50-60°C for one hour has the same effect.

What are the Benefits of Solar Water Purification?

One of the main benefits is its simplicity, making it adaptable for simple communities. The prospect for further research and innovation can make it a perfect tool for worldwide use and a possible cure for the water crisis.

The key features and benefits of Solar Water Purification are the following:



Changes in the microbiology structure of water

Provides clean water for sanitation, hygiene, and consumption

Simple to use

Wide use both in industry and households


Off-grid tool that relies only on the Sunlight without the use of other resources

Low cost

Does not require other energy resources and is suitable for widespread production and use

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A Solar Water Purifier For Home Use

SoDis is an effective way of purifying water, as solar purifiers do not require complex technology or hardware/software components in their production. The only thing that you need is enough exposure to direct sunlight. This makes them a perfect tool for home use.

With their size, products like Gosun or Solvatten will not take more space than a usual suitcase and can fit every household. Whether they are used for outdoor activities or as clean water tanks, they can provide each household with daily needs for water in a matter of only a few hours.

Does a Solar Still Purify Water?

A solar still imitates the mechanisms used by nature to purify water, by using the energy from the sun.

The high heat produced from the solar energy evaporates the water, which then condenses to liquid. This residual condensated water is purified from sediment and the high heat, i.e. its UV radiation kills the germs and living organisms inside it.

As a result, you get water that is safe and can be used for drinking, hygiene and cooking.

Is There Such a Thing as a Portable Solar Water Purifier?

Yes! Due to their simple production and technology, most of the solar water purifiers offered today are portable, can be carried by a single person, and will not take up more space than the average suitcase.

Solar Water Purifier DIY

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There are several ways to build a solar water purifier yourself for your home

Solar water purifiers rely only on using sunlight. This fact makes them easy to produce and even suitable for DIY production at home.

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You can find step by step instructions on how to build a DIY purifier by yourself in this link, using the following components:

  • Wood or sheet metal to build an enclosure about the size of a microwave

  • Reflective material like aluminium foil

  • Black paint

  • White foam insulation

  • Sheet of glass

  • Weather-resistant glue

  • A catch trough

  • A container

  • A heat-absorbent black tray

What you need to do is first paint the outside of the purifier with black paint, as it is commonly known that the black paint attracts the sunlight and increases heat. Then, you need to glue the reflective aluminium surface onto the back and sidewalls of the purifier and glue foam insulation to the bottom.

The water tray needs to be placed inside the purifier and the sheet of glass should be placed on top.

Lastly, you must arrange the dripping part at the bottom where the purified water will be collected. The catch must be angled downward to a container such as a glass or a bottle.

Leave the purifier exposed to strong and direct sunlight for at least 6 hours, and your pure water should be ready for use.

Solar Water Purifier Cost

Buying a solar water purifier is a solid investment that comes with a relatively low price compared to its vast benefits. You can get this for usually $200 – $300.

Disadvantages of Solar Water Purifiers

Regardless of its vast benefits for household use, solar water purifiers come with certain challenges. The key challenge is that solar purifiers require constant and efficient solar radiation, which makes them dependent on weather conditions.

Also, solar water purifiers are effective against microbes and sediment but have a questionable effect on the chemical quality of the water.

Furthermore, solar purifiers require strong solar radiation and therefore are not suitable for the treatment of large volumes of water. This makes their use primarily focused on households rather than high-reach water treatment tools.

Solar-Powered Water Filtration Pumps For Ponds and Pools

By using solar pond pumps, you can get a clean and sustainable solution for maintaining freshwater in your outdoor spaces.

Such pumps come in a variety of forms depending on what you need: from water pumps that circulate water, to aerators that pump in the air and enhance the environment for plants. Also, the solar pumps can create a fountain effect or can be used for larger applications such as swimming pools.

Here you can find the list of 12 best solar pond and fountain pumps.

Other resources relating to solar water purification:

Solar water disinfection

The Water Crisis

Low-cost solar-powered water filter removes lead, other contaminants

How to Make a Solar Still: The Ultimate Purification Device

12 Best Solar Pond Pumps And Solar Fountain Pumps

Solar purifier FAQ

Does sunlight kill germs in water?

  • Yes, the combination of UV radiation and high heat that comes from the sunlight is deadly for germs.

Is it safe to drink solar water?

  • Turbid water can be effectively purified by sunlight making it safe for drinking. However, solar treatment of chemically contaminated water may not result in water that is perfectly safe for use.

Discover your solar saving potential

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