Every year, over 30,000 boreholes fitted with handpumps are installed in rural areas of Sub-Saharan Africa. All will break down at some point. Some will be repaired and return to service. Others will not be fixed and will fall out of use. All will eventually need to be replaced. Up to a third of the waterpoints in Sub-Saharan Africa are out of service at any given time, according to estimates by the Rural Water Supply Network. This doesn’t mean that they can’t be repaired, just that they were out of use when surveyed. Breakdown and repair are normal for any facilities, but if they are not repaired, this has a big impact on users and becomes problematic. Boreholes and handpumps stop working for a variety of different reasons. Some issues can be resolved quickly and easily but others will condemn a water point to a possible untimely demise. Causes of failure can be grouped into three overall categories. Firstly, hydrogeological challenges such as limited aquifer storage, low transmissivity and insufficient recharge may constrain the amount of water that can be withdrawn from a borehole. Groundwater potential can be patchy and prospects for productive wells can vary considerably over short distances. Secondly, poor borehole siting, design and construction can trigger premature failure. Variable groundwater potentials mean optimal siting of boreholes in productive formations is critical. Qualified drilling supervision is required to ensure high standards of design and construction are adhered to with appropriate materials used. Thirdly, human management, demand and financial challenges, including weak supply chains for parts and weak support to communities to keep services running can mean broken down pumps and boreholes go for long periods of time without repair. These failures are well known but it is less understood how important each factor is. Consequently, the water supply sector is not adequately targeting investment or policy towards the issue. People tend to make assumptions about why water sources fail and blame a lack of spare parts, financing, maintenance problems or climate change, for example. But often, the cause is not clear. Finding out the cause of these failures will help to make facilities more sustainable. We’re working with The British Geological Survey, the Overseas Development Institute, Richard Carter Associates and Makerere University, Uganda, to solve this. Together we’ve been building a diagnostic tool to help us identify the cause of borehole and handpump failures. We’re now aiming to use this tool to gather statistically significant information about the most common reasons for a failure. This work has been funded by Economic & Social Science Council (ESRC), NERC and the UK Department for International Development as part of the Unlocking the Potential of Groundwater for the Poor (UPGro) funding.