Safe water through the power of the sun

Safe water through the power of the sun

Project facts

Project type: renewable energy, water, sanitation and hygiene

Project location: Eastern Uganda, Namayingo District

Project standard: Gold Standard VER

Annual emission reduction: 18.000 t

Project start: December 2019

This project provides access to safe water for around 50,000 people in rural communities in Eastern Uganda as many people still depend on open and unsafe water sources like lakes and rivers often leading to diseases like diarrhea, typhoid or cholera.

Offset emissions

Project overview


The project

As in other rural regions in Uganda, access to safe drinking water is a huge issue in Eastern Uganda. Waterborne diseases are a continuous problem for the people. The project is working in Buhemba Sub-​County, Namayingo District, where currently approximately 40% of people don’t have access to safe water. Most of them depend on Lake Victoria for their daily supply of drinking water. The average income in this region is less than 1 USD per day, hence buying clean water or water disinfection technologies are rarely an option for the people in Buhemba.

To manage the microbiological contamination of water, families fall back on the available resources and practices: boiling the water with firewood on inefficient three stone fires. For this, people have to cut down trees for timber/charcoal or collect branches in nearby forests or on their own land, further contributing to local deforestation and drop in forest coverage. However, due to financial reasons many people do not treat their water at all, hence being even more exposed to serious diseases as cholera, typhoid or worms. 

Solar-powered, robust and cost-effective solution for water disinfection
The vision of myclimate’s partner HELIOZ, an Austrian Social Enterprise, is to provide equal access to safe drinking water and to provide knowledge about proper hygiene and sanitation measures as this is a human right and fundamental to the health and well-​being of people. HELIOZ developed a device called WADI (Water Disinfection), a solar powered UV measurement device that visualizes the process of solar water disinfection in PET bottles. Solar water disinfection is a natural process, in which the UV-​radiation of the sun inactivates certain harmful pathogens in the water. The process only requires PET bottles which are everywhere available in the project region. They are filled with contaminated water and are then exposed to the sun. The duration of this disinfection process is determined by the sun’s UV intensity. A smiley face is shown on the WADI device once the process is completed confirming that the water is safe to drink. The method has been tested by the World Health Organization (WHO) and approved as an effective method for household water treatment.

The project provided more than 10,000 households in 45 villages in Buhemba Sub-​County with WADI devices and regular trainings on water use and proper hygiene and sanitation practices. By this, the project will reach around 50,000 people. In a previous pilot project in Uganda, families reported that the WADI device is a very easy-​to-use solution. As in most households, women are responsible for the collection of firewood and providing their families with water, the project solutions will especially benefit the women by saving time and money. The reduced consumption of firewood will also lift the burden on nearby forests and will save CO₂ emissions as boiling on the open three stone fires is prevented. Through the project, the families will be supplied with the necessary resources to disinfect approx. 20 litres of water per day.

Menstrual hygiene management for school girls 
Carbon finance will be used to finance the implementation of the project by HELIOZ Austria and their local affiliate Get Water Uganda and to further enhance its impact by working on complimentary activities in water, sanitation and hygiene (WASH) such as providing menstrual hygiene trainings to young girls and supporting households with installing simple handwashing facilities, pit latrines, etc. Carbon finance will also be used to create income opportunities, especially for women in form of fruit tree planting and establishing plastic collection groups to support recycling of plastics.

This project contributes to the following Sustainable Development Goals (SDGs):
No poverty
Households will save time and money for the collection and purchase of firewood. The project will also initiate income opportunities such as plastic collection and fruit tree planting.
Good health and well-being
Up to 50.000 people will benefit from save water and thus, there are less waterborne diseases such as diarrhea, cholera and typhoid.
Quality education
All 10,013 households have received trainings on proper practices related to the use of water and sanitation. Hygiene measures also with regard to the prevention of Covid-19 are another focus.
Gender equality
Women will save time for the collection of firewood and will have the opportunity for income earning activities. A special focus will be the education for girls on menstrual hygiene.
Clean water and sanitation
Access to safe water is a human right. Each family will be supplied with the necessary resources to disinfect approx. 20 liters of water per day. 
Sustainable Cities and Communities
Four plastic collection groups were formed, each with 30 women. These were then trained with waste management and environmental training. This enabled 407 kilograms of plastic to be collected and sold to local recyclers within one year, generating additional income for the women.
Climate action
Each WADI will avoid up to 2t CO₂ per year from reduced use of firewood for water boiling.
Life on land
The reduced need for firewood also means reduced deforestation, which also helps to preserve the habitat of many animal and plant species. In 2021, an average household saved 1600 kg of firewood.
WADI Erklärgraphik

It only takes five simple steps to get safe water and the water is safe and ready to drink. © Helioz


Village Women Leaders (called Nabakyala) who are leading women associations in each village attending the Local Stakeholder Consultation. © Barbara Oberfichnter, Helioz


WADI functions as an UV indicator showing the users a smiley face when the solar disinfection process is completed. © Barbara Oberfichtner, Helioz

Zwei Frauen mit Kind

WADI in use by Beatrice: It usually takes 3-6 hours until the disinfection process is completed. © Annette Etges-Soroti, Helioz

Familie vor Haus

Family who participated in the pilot project in Soroti District, Uganda. © Annette Etges-Soroti, Helioz

Wasserflaschen liegen zur Desinfektion in der Sonne

Solar water disinfection is a natural process, in which the UV-radiation of the sun inactivates certain harmful pathogens in the water. © Annette Etges-Soroti, Helioz