What is a combined building drain?

A combined building drain is specifically designed to carry both sanitary sewage and storm water through the same pipe system. This type of drainage system is important for managing both wastewater from plumbing fixtures, such as sinks and toilets, and excess rainwater or melting snow, ensuring that both types of waste are directed away from the building to the appropriate treatment facilities.

By utilizing a single pipe for multiple types of drainage, the system can be more efficient in terms of infrastructure requirements and maintenance. However, combined drainage systems may require careful design to prevent overflow and to ensure that the transport capacity is adequate, particularly during heavy rainfall.

Other options describe systems that handle only one type of water or drainage scenario, which does not accurately capture the dual-purpose function of a combined building drain.