What should a subsoil drain system connect through when linked by gravity to a storm sewer?

A subsoil drain system connecting by gravity to a storm sewer requires a backwater valve to prevent any potential reverse flow of water from the storm sewer back into the subsoil drainage system. This is particularly important in areas prone to flooding or where storm sewer systems might become overwhelmed during heavy rain. The backwater valve automatically closes when there is a rise in water level in the storm sewer, effectively keeping excess water from infiltrating the subsoil drains and preventing potential water damage or flooding in the surrounding area.

While other components like a gate valve or gravity discharge pit may have roles in specific drainage applications, they do not serve the same protective function that a backwater valve does in this scenario. The backwater valve is specifically designed to address the risk associated with the elevation differences and the potential for backflow, making it the most suitable choice for safely linking a subsoil drain to a storm sewer.