ABSTRACT
The disposal of foul water and rainwater depends on the proper design of the drainage system and the correct use of appropriate materials. Foul water consists of soil from toilets and bidets and waste water from baths, basins and sinks. Rainwater systems from roofs and pavements should be designed so that the water flows effectively and efficiently to a soakaway or other infiltration system or, if that is not possible, a watercourse. The precursor of the drainage people see on new houses is known as the two-pipe system. Traps were developed to prevent the problem of foul air entering the house. A trap works by retaining water to prevent the passage of odours. Materials used for the vertical discharge pipes have included lead, cast iron, asbestos cement and pitch fibre. In new houses the most common material is plastic. Rather than simply holding the material for collection, a septic tank treats the sewerage that it collects.
