The drainage non return valve can be inserted into the foul pipe inside the inspection chamber. The valve has a single flap, which is in the closed position most of the time. When water leaves the property, the flap opens and will close again once the pressure has rescinded. The valve is designed open with just the pressure from the flush of a toilet. In a flood event, or a back up of water due to blocked rains, the valve is closed shut to prevent back flow. In addition, a stainless steel flap stops rats in the drains.

Benefits of Drainage Non Return Valve

  • Anti-flooding solution, preventing backflow from entering your home from the sewage system.
  • Rat blocker for drains – a single stainless steel flap will stop rats climbing up the drains
  • Stop smells from the drains – with the single flap in the closed position a drain non return valve stops smells entering your property.

Size of Drainage Non Return Valves

The size of the drain pipe will depend on the type of property leading to the drainage system. In the UK, the standard drain pipe sizes are:

  • Residential properties – 110mm
  • Commercial properties – 150mm