The paper presents the problem of working conditions in gravitationalpressure systems simulation. The practical example takes into account the dynamical analysis of a system equipped with 10 pump stations with different functions. Both local press stations, local stations for shallowing network and transit pumping stations between the towns were used. The model allowed to optimize the active volume of the pump station tanks, the selection of pumps, including the frequency of power on and the time of holding the sewage.

The article presents an analysis of water consumption in selected settlement units of Lower Silesia and Lubuskie Provinces, with the number of inhabitants varying from less than 200 to more than 8000. Based on data over several years, values characterizing water consumption in individual systems were calculated, i.e., the indicator of water consumption per capita as well as hourly and daily irregularity coefficients. Consumption during various time frames – in individual months of the year, days of the week and hours of the day - was also compiled. The obtained results were the bases for comparison with values provided by Guidelines, which are the basis for calculating for water demand; and Regulation, which is the basis for billing water consumption, as well as with the results of other authors. Tendencies characterizing water consumption in the subsequent years were also indicated. A typical weekly and daily (24-hour) course of consumption was observed, with the course being characteristic of small settlements with varying numbers of inhabitants.

The article presents the current state of knowledge in the field of estimating preliminary values of storm water subcatchment calibration parameters in the case of using the Storm Water Management Model (SWMM) for building a model of storm water drainage system. The key issue is estimating the runoff width in the case of reducing the network structure and storm water catchments due to the shortening of calculation time and simplification of the model calibration process. Correction of one of the recommended literature methods has been proposed. The assessment was based on the real catchment model with single and multi-family housing. It was found possible to apply the proposed method in the case of reducing systems connected in series.

Using SWMM 5.1 (Storm Water Management Model) software, a model of sewage system functioning in Głogów was developed. It was calibrated based on the results of field studies from the years 2011– 14, while the properness of its activity was verified for the results of measurements carried out during the period 1998–2000. The verification of the model showed acceptable discrepancies between the measured and simulated values of channel depth. Factors which caused differences were indicated and, on the basis of this, conclusions pertaining to further studies were formulated.