The article presents the resultsof experimental studies aimed at verifying the theoretical dependencies of the regulation volume coefficient of two-section stormwater detention tanks (SWDT) on dimensionless input parameters. The studies were conducted on a linear model of a drainage basin for height of the overflow wall 102 mm. A series of tests were carried out, varying the section area ratios and the slope of the outlet pipeline. Experimentally obtained hydrographs of inflow and outflow, as well as fluid accumulation graphs in SWDT, allowed for determining the dynamics of stormwater volume changes depending on the input parameters. The research results confirmed the qualitative and quantitative agreement between theoretical and experimental data, ensuring the accuracy of SWDT regulation volume calculations. Based on numerical differentiation, typical inflow and outflow hydrographs were developed, reflecting the dynamics of flow changes at different stages of stormwater concentration. The influence of the section area ratio and the slope of the outlet pipe on stormwater volumes was also analysed. The obtained results can be utilized to optimize the design of two-section SWDT, improving their operational efficiency during heavy rainfall events.