Urban waterways often improve aesthetics of cities, but also act as stormwater drainage channels. Pollutants accumulating on impervious surfaces are washed off and discharged into waterways, with main contaminants consisting of heavy metals (zinc, copper, lead) and suspended solids. Levels in runoff are well above guidelines relevant for aquatic ecosystems. The main include: traffic (e.g. brake dust, tire wear) and metal roofs (e.g. galvanized iron, copper). Models can be useful in predicting contaminant loads – but require specific input parameters for accurate pollutant build-up and wash-off. It is difficult to obtain this data from real runoff samples due to the variability of natural rainfall events, the length of time required, and the cost of the tests. In this presentation, we introduce the development of method enabling controlled conditions for experimentation.