This section will outline the problems faced by those without access to clean water, the solution provided by the distribution of purifying filters, and the choices that The African Stove Company (TASC) makes when it designs and implements projects distributing these filters.

What are the risks associated with unsafe water supply?

Contaminated water and poor sanitation are linked to transmission of diseases such as cholera, diarrhoea, dysentery, hepatitis A, typhoid and polio. Absent, inadequate, or inappropriately managed water and sanitation services expose individuals to preventable health risks. Inadequate management of urban, industrial and agricultural wastewater means the drinking-water of hundreds of millions of people is dangerously contaminated or chemically polluted. Natural presence of chemicals, particularly in groundwater, can also be of health significance, including arsenic and fluoride, while other chemicals, such as lead, may be elevated in drinking-water because of leaching from water supply components in contact with drinking-water.

Globally, about 1 million people are estimated to die each year from diarrhoea because of unsafe drinking-water, sanitation and hand hygiene. Yet diarrhoea is largely preventable, and the deaths of 397 000 children aged under 5 years could be avoided each year if these risk factors were addressed. Where water is not readily available, people may decide handwashing is not a priority, thereby adding to the likelihood of diarrhoea and other diseases.

Diarrhoea is the most widely known disease linked to contaminated food and water but there are other hazards. In 2021, over 251 million people worldwide required preventative treatment for schistosomiasis – an acute and chronic disease caused by parasitic worms contracted through exposure to infested water.

In many parts of the world, insects that live or breed in water carry and transmit diseases such as dengue fever. Some of these insects, known as vectors, breed in clean, rather than dirty water, and household drinking water containers can serve as breeding grounds. Simple interventions such as covering water storage containers or daily filtration can reduce vector breeding and may also reduce faecal contamination of water at the household level.

Why does TASC distribute ceramic water filters?

We distribute ceramic water filters to address two acute needs: to reduce the risks associated with unsafe water use; and, to meet the demand for high-quality carbon credits to meet regulated or voluntary emissions reduction targets.

Which water filters do you distribute? How do these filters work?

TASC financed the distribution of SPOUTS Purifaaya ceramic water filters in Uganda. SPOUTS have been manufacturing and distributing water filters, in Africa, since 2012. The ceramic water filter sits in a 20-litre plastic container which is perfect for households of up to 8 people. It provides up to 5 years of safe drinking water with replacement filters available.

Technology of Ceramic Filter
How are these filters certified as fit for purpose?

Purifaaya water filters have been used in 5 registered Gold Standard VPAs (Verified Project Activity) for clean water dating back to 2017. In addition, SPOUTS has a 1-star rating water filter rating from the World Health Organisation (which is the level given to filters that filter Bacterial water borne diseases), SPOUTS has certification from the relevant water authorities in Rwanda, Tanzania, Uganda and Nigeria. Furthermore, the Purifaaya filters have undergone and passed testing in Uganda for bottled water grade water purity.

How long do these filters last?

These filters are replaced after a 4-year period. The easy-to-use filter system requires cleaning once every 2-3 weeks and basic care instructions are provided. 

Where were these filters distributed?

TASC funded filters were distributed in the Western region of Uganda in the Toro Kingdom, specifically in the Kamwenge and Kyenjojo districts.

How does the distribution process work for TASC projects?

Distribution starts with sensitization, which is the dissemination of information about the proposed project to local communities. The objectives of sensitization are to maximize the adoption of the new ceramic filters. Sensitization meetings are arranged through the local kingdom authority and village leaders, which helps ensure the project is promoted in a culturally appropriate fashion. Attendees receive a presentation on the risks of unsafe drinking water, the benefits of using ceramic filters and how to effectively use and clean the filters. At this point, the names and addresses of those who would like a filter are collected.

After the presentation and training, the filters are distributed. A mobile application is used to collect data on the recipients, including full name, social security number, proof of identity, address, family size, GPS location etc. The recipients also sign an End User Agreement which confirms that they understand that the project developer retains the rights to monitor the filter usage and the ownership of any carbon credits that may be obtained by doing so.

What is the level of need in Uganda?

According to the United Nations and World Health Organisation’s Joint Monitoring Programme, 19 percent of the Ugandan population relies on unimproved or surface water for their daily household needs. In a population of 45 million this means that 8 million people are drinking from streams, ponds, unprotected hand dug wells and other unsafe water sources. In addition, a further 32 percent has limited access where the water source is likely to be safe but it takes the average person 30 minutes or more to retrieve it because of travelling distance, queueing or both. 

This means that over 21 million people in Uganda are living without basic access to clean drinking water. The vast majority of people rely on water boiling to purify their water and prevent water borne diseases like diarrhoea, typhoid and cholera. 

Further afield and according to UNICEF, Eastern and Southern Africa (ESA) ranks lowest in access to at least basic drinking water services. Over 226 million people in ESA (47 per cent) have no access to at least basic drinking water services. The highest burden is in countries like Ethiopia (61 million), Uganda (27 million) and Tanzania (24 million). Water supply in institutions (schools and heath care facilities) is not any better. Over 78 million (42 per cent) school-age children have no access to drinking water services in schools.

Why are the filters given away for free?

The ceramic filters are given away for free in exchange for the exclusive right to monitor their usage and sell carbon credits associated with their performance. We find this is the most efficient method of distribution. Demanding any cash payment – upfront, financed, or concessionary –dramatically reduces uptake because our target beneficiaries cannot afford it. As these filters directly reduces their risk of illness, we do not find beneficiaries to be less willing to look after filters that they didn’t pay for.

How are emissions reductions calculated from the use of water filters?

According to restrictions outlined in the Gold Standard methodology used for this project, a household is limited to a total daily water use of 5.5 litres per person. However, field consumption tests are completed to determine the volume of water per capita that is used from the filter. This figure is used in conjunction with data on the energy requirements for boiling water, thermal efficiency of traditional fires, and the net calorific value of wood fuel in order to estimate the daily wood use per household and the GHG emissions thereof if they were to boil the water in order to make it potable.

This conservative daily wood use estimation, and its associated emissions from combustion are set as the baseline scenario before the distribution and use of ceramic water filters. As a result of the use of these filters, emission reductions can be calculated from the prevention of the use of wood fuel for boiling and purifying household water.

How does TASC avoid the risk of overcrediting?

The first step to successful monitoring, reporting and verifying (MRV) project CO2e emissions reductions is a complete record of filter distribution. All records must be accessible for spot checking and cross referencing by a third-party auditor. Contact information or GPS locations allows a project auditor to easily contact and visit end users. An auditor must also be able to cross reference pertinent project documentation, including archived filter purchase agreements, financial accounts and distribution records. A custom-built, cloud-hosted database for all data collection and monitoring ensures thorough and real time traceability of each filter.

The second step is the analysis of usage after distribution of the new ceramic filters, and confirmation that wood fuel is not being used for purifying water through boiling. The project scenario relies upon monitoring and usage surveys. The former investigates changes in how much filters are used, how much water they are used for, and seasonal variations in either. The results of a monitoring survey can lead to increases or decreases in the volume of carbon credits that can be issued for each project filter.

Ongoing monitoring visits to households take place at least once a year, with telephone calls being made twice a year to confirm usage and maintenance over the project lifetime.


WHO fact sheet – Drinking Water. March 2022.

UNICEF -Water and Environment.