Backwater is when wastewater from the sewer network is pushed back into the connected underground pipes. Large amounts of precipitation, but also overloading of the sewer system, unplanned discharges, operational failures of pumps or narrowed cross-sections can be the causes.
The municipalities are not liable for damage caused by sewer backwater. They therefore recommend or prescribe backflow protection for buildings that are located in endangered sewer sections.
Since backflow damage is usually not covered by household or building insurance, the homeowner can take out additional insurance. But even here there can be restrictions.
The 3P backflow flap prevents dirty water from entering the rainwater storage tank in the event of backflow. It is suitable for installation in DN 100 pipes.