Simplified Sewerage

Simplified sewerage is a low-cost sewer system that collects all household wastewater (WC wastes and sullage) in small-diameter pipes laid at fairly flat gradients. Simplified sewers are laid in the front yard or under the pavement (sidewalk) or - if feasible - inside the back yard, rather than in the centre of the road as with conventional sewerage. It is suitable for existing unplanned low-income areas, as well as new housing estates with a regular layout. With simplified sewerage it is crucial to have management arrangements in place to remove blockages, which are more frequent than with conventional sewers.

Simplified sewerage is sometimes also referred to as conventional sewerage with appropriate standards, implying that most conventional sewers are overdesigned.

Currently more than two billion people in developing countries do not have access to adequate sanitation. The United Nations have set the target to halve the share of those without access to adequate sanitation by 2015 as part of the Millennium Development Goals. The annual cost of reaching this target has been estimated at US$ 14 billion per year, including both conventional sewers and latrines in rural areas. It is estimated that simplified sewerage reduces investment costs by up to 50% compared to conventional sewerage. Assuming that US$ 10 billion would have to be spent on conventional sewers, the use of simplified sewerage could potentially save US$ 5 billion annually.

The concept of simplified sewerage emerged in parallel in Natal, Brazil and Karachi, Pakistan in the early 1980s without any interaction or communication. In both cases particular emphasis was given to community mobilization, an essential element for the success of simplified sewerage. In Latin America, and particularly in Brazil, simplified sewerage is also known as condominial sewerage, a term that undercores the importance of community participation in planning and maintenance at the level of a housing block (known as condominio in the Spanish and Portuguese use of the term).