Building and Developing

What is the difference between a foul sewer and a surface water sewer?

Foul & Surface water sewer

The foul sewer carries used wastewater to a sewage works for treatment. The surface water sewer carries uncontaminated rainwater directly to a local river, stream or soak away.

Only rainwater run off should be connected to a surface water sewer. All other  waste water from sinks/toilets/baths/showers/washing machines/dishwashers/process water should be connected to a foul sewer.