Conceptually, simplified sewerage is the same as Conventional Gravity Sewerage, without considering the unnecessary conservative design standards, and with design features that are better adapted to the local situation. The pipes are usually laid within the property boundaries, through either the back or front yards, rather than beneath the central road, allowing for fewer and shorter pipes. Because simplified sewers are typically installed within the condominium, they are often referred to as condominial sewers. The pipes can also be routed in access ways, which are too narrow for heavy traffic, or underneath pavements (sidewalks). Since simplified sewers are installed where they are not subjected to heavy traffic loads, they can be laid at a shallow depth and little excavation is required.
Simplified sewerage is also an important sanitation option in peri-urban areas of developing countries, especially as it is often the only technically feasible solution in these high- density areas. It is a sanitation technology widely known in Latin America, but it is much less well known in Africa and Asia. The purpose of this Manual is to introduce this technology and its advantages, so that it can be used more widely in peri- urban sanitation programs and projects to improve the health of disadvantaged communities. However, simplified sewerage is not just for peri-urban areas – it can be successfully and appropriately used in middle-and upper-income areas as well.