ABSTRACT
The design of the drainage system depends on whether it will discharge into a public sewer or an on-site disposal method and, if there is a public sewer, whether it is for soil drainage only or a combined sewer taking both soil drainage and rainwater. The choice of bedding and backfilling materials depends on the depth at which the pipes are laid, their size and strength and the nature of the ground excavated. The materials, design, lay-out and installation of rainwater drains should follow the recommendation for soil drains. A cesspool is an underground storage chamber and its capacity should be sufficient to enable it to hold all the soil drainage of the building until it can be emptied. The Approved Document also refers to the recommendations and data to be found in BS 5906: Code of practice for storage and on-site treatment of solid waste from buildings.
