This dataset comprises raw and processed data from controlled experiments to evaluate the effects of incremental sand and leaf litter accumulation on the hydrological performance of blue-green infrastructure (BGI). The experiments were conducted in a controlled indoor environment using two BGI boxes (each approximately 3.84 m²), replicating a typical infiltration-based BGI system with vegetation, a 6-cm deep substrate layer, and storage layers. Soil moisture sensors and tipping buckets were used to monitor underdrain flow. In one box, sand was gradually added in quantities ranging from 2 to 18 kg·m⁻², while in the other, leaf litter accumulation varied from 0.3 to 1.725 kg. Rainfall was applied to each scenario (16.66 mm·h⁻¹ for Box 1 and 18.66 mm·h⁻¹ for Box 2) for 30 minutes, with at least four-hour intervals between tests. This dataset provides valuable insights into the impact of high pollutant loads on the surface and subsurface of BGI systems during shock events and the maintenance requirements necessary to sustain their hydrological functionality.