Many methods are used to provide or improve on-site sanitation. At one extreme, a project may involve detailed documentation (Grover, 1983) using the "project cycle" approach. At the other extreme, sanitation advances when individual householders build their own improved latrines, often because they have seen similar latrines built by neighbours. Many projects and programmes for improving sanitation lie between these extremes. Planning involves consideration of the local situation leading to selection of suitable types of sanitation. Designs are prepared and construction follows. On completion, and sometimes at intermediate stages, evaluation takes place.
With some projects, the form of planning and development is laid down by procedures which must be rigidly followed if external funds are to be released. However, in many successful programmes, development depends on the action of householders. Planning then leads to selection of appropriate forms of sanitation. Householders may be encouraged to adopt the selected types of sanitation by health education programmes, by technical or material support, or by other measures. The ways in which the different stages of planning and development may be regarded at various levels are shown in Table 9.1.