Foul water & surface drains

Foul water is the waste water discharged from bathrooms, kitchens, utility area etc., as well as from your drive to collect car washing waste for example.

Surface water is rainwater only. In some instances rainwater is also discharged into a foul sewer. Where this occurs, rainwater is discharged into trapped gullies to prevent foul air escaping. This type of system is called a combined system. However in most modern housing developments surface water (also called Stormwater) is discharged into a separate drainage system. The rainwater is then either discharged into a soakaway, water course or other piped system.

A foul water drain must never be connected to a surface water drain.