Scaling WASH Programs for a Sustainable Future

5 min readNov 14, 2023

By Megan Williams, Director of Behavior Change at Splash

In the realm of global development, initiatives addressing water, sanitation, and hygiene (WASH) play a pivotal role in ensuring a better future for communities, particularly in urban areas. Splash, the organization where I work, is dedicated to securing WASH for children in some of the world’s largest cities. I’d like to share Splash’s journey, focusing on our approach to implementation at scale within cities and the principles that guide our efforts.

How Splash Began

Splash embarked on its mission to clean water for kids with a keen awareness of the stark contrast in WASH access between wealthy and impoverished communities in urban areas. This inequality, exacerbated by rural-to-urban migration trends, prompted Splash to initiate change. Beginning with the installation of water filtration systems in Chinese government orphanages, our mission has evolved. Today, we aim to have comprehensive WASH and menstrual health programming in every public school in Addis Ababa, Ethiopia, among other projects globally.

Program Design and Customization

Before delving into Splash’s city-wide approach, it’s essential to understand our comprehensive program. From low-maintenance filtration solutions to custom-designed infrastructure with a focus on girls’ experiences, Splash’s intervention encompasses a myriad of elements. We incorporate environmental nudges to encourage handwashing, like bright colors and mirrors. Our menstrual health programming engages the entire social ecosystem — parents, boys, peers — and of course girls at the center. A suite of behavior change interventions targeting each focus area, whether for janitors, maintenance staff, students, teachers, or administration, is crucial for any intervention.

Leveraging Behavior Centered Design, we engage our audiences throughout the formative, design, and delivery phases. Continuous evaluation, including an external assessment by the London School of Hygiene and Tropical Medicine (LSHTM), ensures effectiveness and relevance.

Three Guiding Principles for Scale

Throughout our journey toward a comprehensive city-wide approach for WASH in Schools, we learned many lessons through success and failure across various countries and projects. I want to focus in on three principles that guide our approach to scale, especially as we look forward to the future: Prove, Persuade, and Phase Out.


Principle One: To refine and prove a cost-effective and impactful model.

Ethically, we shouldn’t invest money and global scale in an ineffective solution. We ask ourselves: what have we done and what do we need to do to prove our model? What are those necessary data points to assure success? We also need to determine and solve for any failures we encounter.

While outputs may not directly address the impact question, they serve as a crucial component in the formulation of a scalable and successful model. In our ongoing initiative, Project WISE, spanning two cities and impacting nearly a million children, we’ve diligently gathered extensive data. This encompasses not only Splash’s interventions across the city but also the activities conducted within schools. Delving deeper, we analyze key indicators at the site level, tracking their performance over time.

It’s through this effort that we have seen a 22% increase in handwashing with water and soap, a 17% reduction in respiratory illness, $11.5 million dollars in government co-investment, and a per-student cost that decreased by 30% over time.

To achieve this goal, we had to initiate the process by assembling a larger global team. Additionally, a dedicated in-house design team was essential to navigate iterations and changes. Implementation involved local teams working directly on the ground. Furthermore, a significant emphasis was placed on monitoring, learning, and evaluation (MLE), supported by a dedicated team to ensure effective oversight and continuous improvement.

And while we were able to accomplish this, it’s still not quite the model we want to move forward with. The next phase for our project is to leverage persuasion.


Principle Two: to convince other implementers, funders, and governments to adopt a WASH in Schools model.

What are we trying to persuade people of? And who are we trying to persuade?

Our objective for the upcoming phase is to establish a network of partnerships, ultimately achieving city-wide WASH in Schools initiatives across four additional countries, targeting 2–3 cities per country. Instead of establishing complete Splash teams in each country, our strategy involves persuading governments to invest, encouraging existing local organizations to partner, prompting commercial markets to fulfill supply needs, and engaging schools, parents, and students in the process.

To accomplish this, our initial step involves gathering city-wide data to comprehend the overall context, determine the necessary budget and effort, and utilize this data as a foundation for program design. Close coordination and collaboration with the government is crucial for further expansion, this time executed through local implementers. This approach emphasizes co-design, leveraging the unique strengths of each party, and restructuring the global team to prioritize support over oversight. Additionally, we maintain our commitment to ongoing evaluations to ensure the success of the initiative.

Deployment models look very different through a partnership lens — with 5-year implementation cycles as the goal.

Phase Out

Principle Three: to develop a sustainable, ethical way to transition.

What characterizes an ethical and effective exit? As a smaller organization, our aim is not to grow in perpetuity. Instead, we aspire to develop tools for other actors to utilize, aid in their adaptation to new contexts, leverage insights from our direct implementation, and foster connections between partners. Ultimately, our goal is to create a robust network of support and resources, allowing us to step back and empower local partners to excel and surpass our own capabilities.

How can we achieve this? We plan to adopt a multi-city, multi-country approach, creating a diverse set of examples that serve as a foundation for replication. This involves establishing a knowledge management hub that is both clear and engaging, ensuring accessibility. We also aim to transition towards a consulting role to aid new initiatives in their program design, offer technical assistance, and share our experience in project management. Securing funding and facilitating connections between funders and local implementers are key components of our strategy.

Splash’s journey exemplifies a thoughtful and strategic approach to scaling WASH programs in urban areas. We are not just addressing immediate needs but laying the groundwork for lasting change. In this way, we believe we can contribute substantially to achieving the Sustainable Development Goals (SDGs) and ensure every school has comprehensive WASH+MH facilities so every kid can thrive.




Clean water, clean hands, clean toilets, and menstrual health support for kids in urban poverty — co-developed with local governments.