This study attempts to examine the factors affecting the residential water demand level in the city of Kozani in Greece. Based on an 8-year (2005–12) detailed sample of residential water demand panel data, the values of the water price (WP) elasticity of residential demand are identified, and the influence of socio-economic and demographic factors and climate conditions on water-use levels and trends are analyzed. The system's response in terms of system input volume is examined (through the simulation model developed for the network and a pressure management (PM) application) for different scenarios of increased and decreased WP levels. Various scenarios for the real losses were examined, starting from their current level (current annual real losses), down to their economic level (economic annual real losses) after implementing PM measures. The overall objective is to determine and record the overall reaction of consumers to the changing WPs as a result of the full water cost principle implemented.