Payment modalities for low-income households

Stef has worked with governments, NGOs, development banks and consultants across all areas of the international water sector: from analysing the lifetime costs of services and how they can be financed, to developing institutional arrangements and monitoring their effectiveness. He brings that analytical rigour to strategic advisory work, based on more than 25 years of experience across more than 25 countries in Europe, Latin America, Africa and Asia – turning research findings into practical decisions and investment strategies. In an organisation known for thought leadership, he builds the tools that enable others to put those ideas into action.

Over the past years, he has taken on a more internal management and leadership role, with responsibilities for business development and financial management. In 2026, Stef has become CEO of Riva The Netherlands.

He has an MSc in Irrigation and Water Engineering from Wageningen University, and is based in The Hague.

A few highlights

• 25 years of generating research, evidence and tools that have helped reshape how governments, INGOs and development banks across Latin America, Asia and Africa approach the life-cycle costing, financing and sustainability of water services and water resources management
• Director, IRC Netherlands (since 2024) – executive responsibility for a team of 30, leading business development and strategy across the Netherlands and Europe, and spearheading IRC's transition to a nationally-led network model
• Managing large-scale grant programmes including “Building sustainable WASH systems”(funded by the Dutch Ministry of Foreign Affairs) at 1.5 million Euro/year since 2017, and  WASH Systems for Health Facility (funded by the FCDO of the UK Government), a  £3 million knowledge programme across six countries, linking essential water and sanitation systems strengthening to health impacts
• Pioneer of the multiple-use water services concept – designing systems that serve domestic and productive water needs simultaneously
• Advisory work with the Inter-American Development Bank, World Bank, DGIS, Agence Française de Development as well as with international NGOs
• Served terms as Executive Steering Committee member, Rural Water Supply Network; Secretary, Multiple Use Services Group; Editorial Board, Water Alternatives journal
• Working languages: Dutch, English, Spanish and Portuguese

Lemessa Mekonta began his career in groundwater development for human uses, which involves mapping groundwater occurrence and dynamics – learning to read what lies beneath the surface, and how it behaves. That instinct for going deeper than what is immediately visible has stayed with him. For two and half decades, it has shaped how he reads institutions and systems and discovers what’s holding them back. 

He works with governments and institutions across Ethiopia to build the planning, financing and operational systems that make essential services reliable over time – from developing district-wide master plans with local governments to strengthening town water utilities to withstand the pressures of a changing climate. His expertise spans urban and rural, formal utility and household self-supply, highland and pastoral lowland. He brings the same discipline to each: understand the whole system before designing any part of it.  

What makes Lemessa rare is a trajectory that most advisers lack. He started his career inside Ethiopia's government – as a geologist/hydrogeologist for Oromia's Water, Mineral and Energy Bureau, from junior to senior positions including as a department head for Water Resources management; while with government, Lemessa was also a board chair for a town water utility for five years. He then built and ran his own consultancy for seven years before joining Riva. He has worked inside every part of the system he now helps to reform, and understands what each sector needs, how each thinks, and where they fail to connect. He leads the national Agenda for Change coalition in Ethiopia – convening a collaboration of more than a dozen organizations, involving government, INGOs, multilateral and bilateral organizations around a shared approach to systems strengthening. He holds an MSc in Hydrogeology from Addis Ababa University, and a postgraduate certificate in Engineering geology and hydrogeology from the University of Tübingen, Germany; and he is based in Addis Ababa.  

A few highlights  

• 25 years of systems leadership across Ethiopia's water sector – spanning government, private consultancy and the NGO sector  
• Water resource development including mapping and construction with focus on groundwater for different uses 
• Research on Rural water supply operation and maintenance, including governance, supply chains and finance 
• Lead, Agenda for Change Ethiopia collaboration – convening 13 plus organisations including government and development partners around a shared systems strengthening approach 
• Co-chair national WASH finance working group 
• District-wide master planning with local governments, translating long-term visions for water and sanitation into life cycle costed, implementable roadmaps  
• Urban water utility strengthening– building the governance, financing and operational capacity that makes town utilities viable  
• Research on household self-supply and multiple use water services (MUS) as complements to formal systems – including published work on multiple-use water services in Ethiopia  
• MSc in Hydrogeology from Addis Ababa University, and postgraduate certificate in Engineering geology and hydrogeology from the University of Tübingen 
• Working languages: Afan Oromo, Amharic and English