Assessment of the correctness of the calculation of fees paid by the city of Lodz to the Polish Waters

Scope of work performed:

  • Verification of the level of fixed and variable fee paid by the City of Lodz to the Polish Water.



  • The new Water Law has implemented fees for the discharge of rainwater and snowmelt. These fees have become a significant cost in Lodz’s budget.
  • While the legislation defines the basis for calculating these fees, it does not specify how to calculate either the amount of actual outflow in a given quarter (for the variable fee) or the maximum amount of water specified in the water permit (for the fixed fee)



  • Based on the analysis of the topography of the area and the graph of the KD network, the actual extent of the catchment area was determined using GIS tools.
  • In the next steps, the reliability of the precipitation data sources used was verified, as well as the match between hydrological outflow calculation methods and catchment conditions.



  • Updating the size of the total area and the reduced area to actual has resulted in a significant reduction in the actual level of the variable fee.
  • Changing the approach to input data sources and calculation method to one suitable for local conditions makes the output data more reliable.
  • In the case of Lodz, the proposed approach also contributes significantly to lowering reliably charged fees.