The Stichtse Rijnlanden is investigating the cause of the malfunction. Normally the system notifies you if there is a problem, but because everything went black, this was not the case now. “It rarely if ever happens that the entire operating system goes down. It is still a mystery to us, but we are doing everything we can to get to the bottom of it. It is very important to find out what events led to this. We are also investigating what the consequences are for the surface water,” said a spokesperson. “An advantage is that it has rained a lot recently. The water is therefore diluted and drains away faster.”