A large-scale implementation of individual water meters in water charging systems has created problems with a water shortage that have to be settled between real estate managers and water and sewage utilities. The article presents the observations and experiences from operation of a water metering system at the Krakow agglomeration. The studies have confirmed that many small leaks in installations, taps, faucets, flush toilets as well as system failures and the incidences of water stealing are still the factors responsible for significant differences in the water balance in the apartment buildings.