[17-09-2008] The focus of the General Public Sewer System Plan in the City of Hranice is not the assessment of the conventional drainage, but the assessment of the future condition in accordance with the sustainable development principles. Following the given systemic rules, a background analysis has been worked out, the area potential has been determined, a mathematic model has been developed including continuous runoff simulation through the decentralized drainage system and new rules for this type of drainage have been integrated into the City‘s General Development Plan. What is the significance of such a general public plan for the city management? What is necessary to do in order to use it properly and effectively?