A practical model to integrate both leakage and pressure-dependent demands in extended period simulation models of water distribution networks is proposed. Given the pressure relationship for both terms, their coefficients associated to each node and time period are obtained from a minimum data set, constituted basically by the global hydraulic efficiencies for delimited areas and other general parameters, all of them usually available for water companies. The main aim of the proposed model is to get more reliable results when simulations are carried out for new scenarios such as pressure reduction for leakage control, failure of critical components of the network (water treatment plant, pumping station, main trunk, etc) or restrictions during an extended drought. Important conclusions can be obtained from the new integrated model on leakage assessment and management policies.