Method for detecting leaks in a network, having the steps of: - determining consumption profiles (13-1 - 13-n) for each consumer (12-1 - 12-n) in the network; - calculating pressure profiles (14-1 - 14-n) and/or flow profiles (15-1 - 15-n) for the network on the basis of the determined consumption profiles (13-1 - 13-n), at least one simulation of the network being carried out when calculating pressure profiles (14-1 - 14-n) and/or flow profiles (15-1 - 15-n), the simulation being carried out more than twice, in particular; - reducing the data in the calculated pressure profiles (14-1 - 14-n) and in the calculated flow profiles (15-1 - 15-n), the data in the simulation being reduced when reducing the data on the basis of a mathematical series expansion, in particular a series expansion based on the proper orthogonal decomposition method (POD method); - placing first sensors (5-1 - 5-n) and at least one second sensor (6-1 - 6-n) in the network, the first sensors (5-1 - 5-n) and the at least one second sensor (6-1 - 6-n) being designed to measure pressure and/or flow quantities, the positions of the first sensors (5-1 - 5-n) and/or of the at least one second sensor (6-1 - 6-n) in the network being determined on the basis of the POD method when placing first sensors (5-1 - 5-n); - calculating pressure values and/or flow quantities for the positions of the at least one second sensor (6-1 - 6-n) in the network on the basis of the measured values (7-1 - 7-n) from the first sensors (5-1 - 5-n) and the reduced data; - determining the difference between the calculated pressure values and/or the calculated flow quantities and the pressure values measured by the respective second sensor (6-1 - 6-n) and/or the flow quantities measured by the respective second sensor (6-1 - 6-n); - outputting a warning signal if the determined difference is above a predefined threshold value. - determining consumption profiles (13-1 - 13-n) for each consumer (12-1 - 12-n) in the network; - calculating pressure profiles (14-1 - 14-n) and/or flow profiles (15-1 - 15-n) for the network on the basis of the determined consumption profiles (13-1 - 13-n), at least one simulation of the network being carried out when calculating pressure profiles (14-1 - 14-n) and/or flow profiles (15-1 - 15-n), the simulation being carried out more than twice, in particular; - reducing the data in the calculated pressure profiles (14-1 - 14-n) and in the calculated flow profiles (15-1 - 15-n), the data in the simulation being reduced when reducing the data on the basis of a mathematical series expansion, in particular a series expansion based on the proper orthogonal decomposition method (POD method); - placing first sensors (5-1 - 5-n) and at least one second sensor (6-1 - 6-n) in the network, the first sensors (5-1 - 5-n) and the at least one second sensor (6-1 - 6-n) being designed to measure pressure and/or flow quantities, the positions of the first sensors (5-1 - 5-n) and/or of the at least one second sensor (6-1 - 6-n) in the network being determined on the basis of the POD method when placing first sensors (5-1 - 5-n); - calculating pressure values and/or flow quantities for the positions of the at least one second sensor (6-1 - 6-n) in the network on the basis of the measured values (7-1 - 7-n) from the first sensors (5-1 - 5-n) and the reduced data; - determining the difference between the calculated pressure values and/or the calculated flow quantities and the pressure values measured by the respective second sensor (6-1 - 6-n) and/or the flow quantities measured by the respective second sensor (6-1 - 6-n); - outputting a warning signal if the determined difference is above a predefined threshold value.