Mayor Sabine Groß climbs onto the green roof of Pressehaus Bintz Verlag

The City of Offenbach's stormwater regulations have been in force since July 2022 to combat climate change. This regulation requires new construction projects to use or infiltrate rainwater on their own property instead of discharging it into the sewer system.

On June 3, 2025, Mayor and Climate Officer Sabine Groß accepted the invitation from Offenbach-Post to find out more about the implementation of the rainwater bylaws during the construction of the extension on the premises of Pressehaus Bintz Verlag. In addition to two green roofs on the new building, another green roof was installed on an existing building.

Green roofs help to delay the so-called "runoff peak". This is the large amount of water that falls in the first few minutes of a downpour. This prevents flooding in the sewer system. As infiltration was not possible on the property due to contamination, a cistern with a capacity of six cubic meters was also installed. It is used to water the newly planted trees.

In addition, a rainwater retention basin with a capacity of 220,000 liters was created under the parking lot of the publishing house. This corresponds to around 1,470 bathtubs full of water - enough to operate a city fountain for weeks. The basin collects the water from the large canopy and releases it into the sewage system in a controlled manner to prevent flooding.

The rainwater regulations stipulate that "every drop" should be used on your own property. The aim is to store or use the water through infiltration or measures such as cisterns or green roofs.

"In recent years, we have experienced more and more extreme weather: it hardly rains, then it rains so much that flooding is imminent. At the same time, temperatures are rising, which is very stressful for children and the elderly. That is why it is so important to make Offenbach a 'sponge city' - water should be absorbed like a sponge. This reduces the risk of high water and flooding during heavy rainfall and ensures cooling evaporation in hot weather. Implementation is a joint task that requires everyone's help. During my visit to the Offenbach-Post, I could see that the construction project is moving in this direction. My thanks go to the publisher for the good implementation of our rainwater bylaws and for sending a strong signal for our city," says Mayor Sabine Groß.