Non-return Valves - Sewage & Drains

Non-return valves (also known as backflow or one-way valves) are devices fitted to sewers and drains to prevent floodwater or sewage from flowing back into a property. During heavy rainfall or flooding, main drains can become overwhelmed, causing water to reverse flow — often leading to foul flooding through toilets, sinks, showers, or external drains. A non-return valve allows waste water to exit the property as normal but automatically closes if water tries to come back in. These valves can be installed in toilet pipes, floor drains, or external manholes, and are a key part of flood protection in homes and businesses at risk of surface water or sewer flooding.