In July 2018, the Ministry of the Environment, Climate Protection and the Energy Sector Baden-Württemberg published the decree ‘Messen an RÜB’ (measuring at rainwater overflow basins). It stipulates that before the end of 2024 all rainwater overflow basins in operation need to be retrofitted with measuring equipment to record their filling and overflow behaviour. The concept for the retrofit had to be finished by the end of 2020. Eigenbetrieb Stadtentwässerung Böblingen tasked IWR GmbH with the creation of the concept for their rainwater basins. At the end of last year, the concept design report was successfully submitted. It comprised the retrofitting of 18 structures of centralised rainwater treatment until the end of 2024. Six of the basins will already be upgraded in 2021.