Sustainability of WASH interventions remains a challenge despite progress and evolution in thinking in the sector. Traditional approaches based on a community engagement model have failed to connect communities to the broader enabling environment necessary for ongoing WASH services. The Australian Government's AUD103 million Civil Society WASH Fund (2013–2018) mobilised civil society organisations (CSO) to engage with the WASH enabling environment by supporting the performance of WASH sector ‘change agents’—people with primary responsibility for WASH service delivery. This approach represented an overt shift away from previous phases that saw CSOs directly delivering infrastructure and services into communities. This paper presents three tools – Strategy Mapping, Context Mapping and the Change Agent Assessment Tool – developed by the Fund's M&E Panel to test the Fund's Theory of Change (ToC) that greater engagement with the enabling environment would enhance the sustainability of WASH services. These tools were primarily developed to facilitate structured reflection by project teams about the relevance and effectiveness of their approaches, but ultimately provided valuable datasets that appear to authenticate the Fund ToC – suggesting that investing in the enabling environment for WASH services is a more sustainable policy proposition than investing directly in community WASH infrastructure and services.