NALA Foundation | WASH on Wheels - Cost-Effectiveness Report

03 May 2023
Dr. Rachel Golan and Shahar Aviram

Cost-effectiveness Research Report: The WASH on Wheels Project Maintaining water infrastructure in primary schools in Ethiopia to achieve the 2030 SDGs

This report analyzes the cost-effectiveness of the WASH on Wheels (WOW) project implemented by NALA, an international public health non-governmental organization (NGO), specializing in the elimination of diseases of poverty associated with the lack of clean water. The WASH on Wheels was funded by the Bill & Melinda Gates Foundation and Shalom Corps.

The Intervention

  • The WOW project aims to restore access to safe water in schools in Ethiopia, to decrease the prevalence of hygiene-related diseases among schoolchildren and the local community, therefore reducing mortality, suffering and poverty. This, in alignment with the United Nations Sustainable Development Goal (SDG) #6 - Ensure availability and sustainable management of water and sanitation for all.
  • The project consists of expert local technicians with vehicles carrying maintenance tools and spare parts, which travel to fix existing, non-functional water infrastructures on school premises. To ensure sustainability, the project also includes basic maintenance training of representatives from the district's water sector (“WASH Fellows”), enabling them to fix WASH infrastructure malfunctions in their respective districts.


  • The data used to conduct the following cost-effectiveness analysis is mainly primary data, collected and documented by the project’s team in the field. Detailed documentation of the project’s expenses was provided by NALA. Other data, regarding the schools and the beneficiaries, was either provided by local government representatives, or gathered from secondary sources.
  • The analysis considers the outcomes of the intervention between May and December 2022, and all the costs that contributed to these results.
  • The total inflation-adjusted cost of the project is estimated at 265,900 USD, with 159,300 USD for the set-up phase (May 2021 to May 2022) and 106,600 USD for the first implementation phase (May-December 2022). 
  • Based on follow-up visits to 20 of the treated schools, the mean time for which WOW fixes are expected to provide water access until failure (MTBF) is at least 600 days (95% confidence level), and most likely around 1500 days (4 years).

Cost-effectiveness Analysis

  • Given various constraints and considerations, we focused the analysis scope on the project’s outcome of providing water access for schoolchildren, without assessing the effect on prevalence of hygiene-related diseases.
  • The analysis considers the number of fixes conducted, number of direct beneficiaries, the MTBF, number of school days per year, the school attendance rate, and the costs of the WASH on Wheels project.
  • The first phase of the WASH on Wheels project provided water access to 215 schools, for approximately 170,000 children. For each child, the project is expected to provide, on average, water access at school for 640 attended school days, and with a 95% confidence level - an average of at least 250 school days. Both, considering no additional fixes after failure (e.g. by the WASH Fellows).
  • Thus, we estimate that every 1 USD invested in the WASH on Wheels project, is equivalent to providing water access for about 400 attended school days for 1 child, and with a 95% confidence level - for at least 160 school days.


We discovered effects that were not expected, and therefore were not measured.

  • The surrounding school community unexpectedly engaged with the WOW team, contributing labor and materials.
  • Schoolchildren often use the water for drinking purposes as well, which might result in negative or positive impact, based on the quality of the water provided.
  • We hypothesize water availability in schools allows improved cleaning of toilets, which may lead to more schoolchildren using them. Thus, potentially reducing open-defecation and decreasing prevalence of hygiene-related diseases.

Limitations and Uncertainties

  • The MTBF (Mean Time Between Failures) calculation is derived from a relatively short follow-up period and a limited sample size. Therefore, the variance of these results are relatively large.
  • The number of school days per year and the children’s school attendance rate are currently based on a single secondary source. This may lead to an underestimation or an overestimation of the project’s impact.
  • The usage of the WASH facilities by the wider community was not assessed, and future fixes by the already-trained WASH Fellows were not considered. By not considering these outcomes, it is probable that the assessment underestimates the cost-effectiveness of the project.
  • We assumed no counterfactual impact. Meaning, we assumed maintenance of WASH infrastructures would not have occurred in the given time and places by other partners. If this assumption is wrong, it could result in an overestimation of the cost-effectiveness of the project.

Room for More Funding

  • Given that water access in schools in many countries in the global south is scarce, funding for continued implementation is significant. Next steps for the project include additional research and scale-up at the regional, national and international level, with implementation by the local government and technical support provided by NALA. These steps will require funding of approximately 505,000 USD.


  • The cost-effectiveness analysis revealed that low investment is needed to achieve substantial progress towards achieving the UN Sustainable Development Goal #6.

  • Moreover, by repairing existing infrastructures, the WOW project enhances the sustainability of investments made in water infrastructure. Thus, allowing these investments to yield more substantial and enduring impact.
  • We plan to conduct additional data collection and research regarding the project - to further validate our current assessments, to assess the impact on diseases prevalence, poverty and education, and to improve the cost-effectiveness of the project.
  • Furthermore, we have identified impact measurement and cost-effectiveness assessments as essential for NALA, and we intend to apply them in more projects. 
WASH Financing