When thinking of the risk of flooding the common thought is to think about access of water through such avenues as doors and air bricks, however commercial and domestic flooding can also happen from the back-filling of sewerage pipes, dishwashers, showers, etc.
For internal flood protection the watertight non-return valves prevents backflow and water from entering the property through this access. The backflow of sewage entering a property can be extremely distressing for both business and homeowners. It will also mean a longer clean-up operation afterwards with the majority of furniture being thrown away to reduce the risk of health complications afterwards.
The UK is seeing more of this type of flooding due to climate change, sewers under heavy rainfall become overwhelmed and this type of rain can displace dirty water and bring it to the surface. Securing your property with internal flood barriers is just as important as protecting it externally as well.