Method for inspecting, in real time, the quality of water of a drinking water delivery network comprising, on the one hand, on connections for consumers, consumption meters (9a) fitted with remote-reading devices, and, on the other hand, on-line analysers (10a) distributed at supervision points on the network in order to measure at least one parameter of water quality. The meters (9a) are fitted with remote-reading devices and the consumption data of the various meters (9a), and the measurements of the analysers (10a) are transmitted to a programmed computing unit (A) with a kinetic model of decrease of the quality parameter in question; the computing unit (A) permanently updates the hydraulic model according to the consumption data received from the meters (9a, 9b etc.); the computing unit (A) establishes expected estimated values of the concentration in the water of the parameter in question at the various supervision points of the network, and a prewarning system (w) makes a comparison between the estimated values of the quality parameter and the values measured at various points of the network, a warning being triggered when the difference between the measured value and the expected estimated value exceeds a predetermined threshold.