Berlin is a dry city and is becoming drier. Groundwater levels are reducing, but there is no increase in precipitation, meaning there is less water all around. On the other hand, the style of precipitation is changing – longer drought periods dry out the topsoil, and heavier downpours are unable to seep into this dry topsoil.
Rather than replenish ground water supplies, heavy rain often flows straight into the sewer systems, not serving its purpose (providing drink for plants and trees!), pulling pollution from streets into the water systems and causing wastewater overflows into rivers and lakes. This overflow dirties the water, which compounds a problem when water levels are already low.
Collecting rainwater at every opportunity makes sense. The less that flows from our house pipes down the road to the sewers, the better.
The Raincheck goal is to collect enough rainwater to avoid using treated drinking water in the garden. Since drinking water is so precious using it for gardening purposes feels like an extravagance.
The need to water a garden is important. A garden serves many purposes – it is a place of relaxation and leisure; it is a place for children and their friends to have fun. But in addition to this it is a small plot of land in this wonderful city where wildlife and biodiversity are supported.
For a very detailed analysis of the water situation in Berlin in the years 2018-2023 this study is very accessible: https://nhess.copernicus.org/articles/25/1293/2025/#abstract
Raincheck 