Project implementation (or project execution) is the phase where visions and plans become reality. This is the logical conclusion, after evaluating, deciding, visioning, planning, applying for funds and finding the financial resources of a project.

The implementation of projects in sustainable sanitation and water management is complex. It requires the coordination of a wide range of activities, diverse institutional arrangements, and different time frames (DFID 1998). There is not one typical project in water and sanitation, as the actions may vary from the construction of new infrastructure to the introduction of new ways of working. Projects in this area cover issues such as: social development, health, environmental sustainability, institutional strengthening, technical implementation, pilot plants, service delivery, social marketing, hygiene promotion, sanitation promotion and capacity building.

It is important to take into account that independently of the nature of the project, implementation takes time, usually more than it is planned, and that many external constraints can appear, which should be considered when initiating the implementation step (i.e. seasonality in the availability of community engagement/resources) (NETSSAF 2008).