The London Combined Sewerage System

The London Combined Sewerage System is a comprehensive infrastructure designed to collect and transport both household wastewater and rainwater runoff through a network of large underground pipes. This system ensures that sewage and stormwater are efficiently conveyed to treatment facilities, especially during heavier rains when combined flows can increase dramatically. Its goal is to prevent flooding and protect waterways from pollution, although during heavy storms, excess combined flow sometimes bypasses treatment and is discharged into rivers, a practice known as combined sewer overflows. Overall, it plays a vital role in maintaining public health and environmental quality in London.