There are two basic systems in use for the disposal of waste water. These tend to relate to the age of the property.
Older waste drainage system
The waste water from the kitchen sink, basins and baths is all drained to a gulley outside. This has a water trap to prevent smells emerging from the drains.
The waste from WCs is routed directly to the mains drainage via a larger vented pipe.
Newer waste drainage system
All waste water is fed into one large vented drainage pipe which connects to the mains drainage.
All waste drainage systems
It is essential to identify the correct route for disposing of waste water from your property.
It is illegal, for example, to dispose of effluent into the surface water drainage system.
This system is for the collection of rainwater and frequently connects to nearby streams which would become contaminated by the disposal of sewage.