Impacts on Groundwater Quality from Stormwater Infiltration (2025–2026)

Infiltration of stormwater is a common approach in sustainable stormwater management, used to reduce pressure on drainage systems, attenuate flows, and support the local water balance. At the same time, stormwater may contain contaminants from urban environments, such as metals and organic substances, which can potentially be transported into groundwater by infiltration. Although infiltration is often highlighted as an environmentally beneficial solution, there are still knowledge gaps regarding its long-term effects on groundwater quality, particularly under varying conditions and for different types of pollutants.

This project investigates how stormwater infiltration may affect groundwater quality. At an existing pilot-scale test setup consisting of three infiltration basins, stormwater will be infiltrated to enable comparisons of water quality before and after infiltration, thereby allowing an assessment of potential risks to groundwater. By tracking changes in water quality along the infiltration pathway, the project will generate a basis for evaluating which substances may reach the groundwater and to what extent. The focus is on metals as well as several groups of organic contaminants.

The aim is to improve understanding of the risks associated with stormwater infiltration to groundwater and to identify how stormwater runoff should be managed to ensure long-term protection of groundwater quality.

The project is funded by the Swedish Environmental Protection Agency.