Early in the planning process the extent of the programme or project must be assessed. This involves making an estimate of the number of people or households who will be covered. A house-by-house survey may be undertaken, or the necessary information obtained from health staff, government departments or local leaders.
A list is drawn up comparing the needs of different areas. Priority should be given to people with especially poor facilities for excreta disposal and areas with a high incidence of diseases associated with poor sanitation. Areas with a high population density or congested housing may justify special attention. However, houses intended for temporary occupation may warrant less attention than permanent buildings.
Other factors that influence the selection of priority areas are the interest of the local communities in sanitation improvements and their record of participation in other projects. Ability and willingness to contribute financially may be other criteria for the selection of priority areas. Projects generally depend on a financial contribution from householders; occasionally priority is given to people most likely to pay or those willing to try new ideas. For projects that are externally funded, the poorest people may be selected for preferential treatment, on the assumption that better-off families should pay for their own latrines.