An exit strategy in the context of emergency water supply interventions is a planned approach of why, what, when and how implementing organisations will end their water– supply related humanitarian engagement. This process should be considered and planned for from the start of activities. Addressing the exit strategy at an early stage of an intervention provides transparency to partners and promotes a seamless handover to respective government departments or development agencies. Overall, an exit strategy includes the process of transitioning, handingover and possibly decommissioning infrastructure and exiting or disengaging from activities, projects, programme areas or countries. This is particularly important once the acute phase has passed and should be implemented as soon as basic water supply services are (re-)established at a level that successfully reduces the vulnerabilities. For post-acute, chronic and protracted crises, exit criteria are applied that compare the advantages and costeffectiveness of a sustained humanitarian intervention with those of an intervention led by local authorities and agencies or other donors and/or partners. As with other water supply considerations, exit and transition strategies are context dependent.

Exit strategies must also align with national strategies and policies X.3. If the local situation allows, they should be carried out in coordination with the government and/or relevant developmental actors to jointly define the scope and focus of the interventions to ensure a smooth transition. Implementing partners must specify when and how project support will be terminated and handed over to the local government, other local organisations or service providers capable of sustaining/maintaining the achieved service levels or clarifying whether and how projects will be followed up (e.g. by another phase with the potential for follow-up funding to continue WASH activities where necessary). The following sustainability criteria should be addressed as early as possible to allow for a successful hand-over to local governments or other developmental actors and guarantee the future viability of the system: 

• Technical sustainability: Water supply interventions must support locally appropriate technologies
  and designs as well as available and affordable local construction materials. Water systems must be in sound technical shape at the time of a handover to a local entity. For water supply services to remain operational, interventions need to be balanced between technically feasible solutions and what the affected population, local government entities or service providers desire and can manage after the project ends.
• Financial sustainability: The respective costs for the long-term O&M of water supply infrastructures must be considered as part of the technology selection. While cost recovery is not a priority in the acute humanitarian response, awareness of the protracted financial consequences of (re-)establishing water supply services is essential from the outset.
• Socio-cultural and institutional sustainability: Water supply interventions need to consider local acceptability and the appropriateness of the implemented technologies, convenience of the services, taste and odour of water, perceptions of users and service providers, gender issues and impacts on human dignity. When water facilities are provided for displaced people, care should be given to maintaining a similar service level to host communities. Actions need to be taken to ensure that hygiene promotion activities and behavioural change interventions X.16 are sustainable. Ownership of the infrastructure, including responsibilities for O & M, must be clearly defined. To identify the requirements of an enabling environment, it is important to know the capacity of the affected population, communitybased organisations, service authorities and service providers to plan, manage and monitor water-supply services, including financial aspects, asset management and O & M. Organisations and structures (public, private and community) need to be in place to provide the necessary support.
• Environmental sustainability: The impact of interventions on local water resources needs to be assessed prior to the intervention. To build resilient water supply systems, the design needs to be adapted to the identified risks. The inclusion of integrated water resource management and water safety plans X.8 is considered an integral part of the response. The design involves a comprehensive evaluation of water resources; an assessment of current and future demand; the definition of roles and functions of local and national authorities; and the identification and enforcement of water-use rules and/or master plans for water/wastewater systems in urban settings. In acute scenarios involving temporary solutions, it may be necessary to consider dismantling and decommissioning water supply facilities. The implementing organisation responsible for construction and service provision is usually also responsible for decommissioning.