So far, I have never seen the bottom of the cistern, provided it was really only used for my garden. So for my garden with about 240m² of lawn and some border planting, it is quite sufficient - however, there are also 170m² of roof area connected to it, and that's why a summer thunderstorm is enough to refill it well. Yes, I am painfully aware of the disadvantages of underground systems, especially a continuous network obviously means a complete garden redesign. What I still find very tempting, as mentioned, is the lower water consumption but also the neighbors who are already setting up the bonfire again because there is a water shortage in Brandenburg and I am watering with my rainwater in an area with a water surplus. I spare myself the discussion when the irrigation is not visible. What of course does not work with the underground system is the targeted control of the sprinkler via Home Assistant to deter unwanted visitors.