A cesspit overflow occurs when a sealed underground tank used to store sewage at properties off the mains drainage network reaches capacity, or when its inlet drainage backs up due to a blockage. Cesspits are designed to store all wastewater without discharge, and so depend entirely on regular emptying by a licensed tanker. In London, cesspits are uncommon but still found at some outlying properties, particularly older houses on the rural fringe. Symptoms of overflow include foul water rising from inspection chambers, gullies and low-level fittings. Engineers usually address common causes by arranging tanker emptying urgently, then inspecting the chamber and inlet drain. Where the cesspit is undersized or failing, replacement with a compliant package treatment plant under the General Binding Rules and BS EN 12566 is often considered.
Cesspit overflow
Sewage rising from a cesspit because it has reached capacity or its outlet is blocked.
