Swales are commonly used to manage stormwater runoff, but their design often focuses on water flow rather than pollutant treatment. Research shows that grass swales with check dams are best for reducing runoff volume and removing sediment and heavy metals. Wet swales are most effective for removing nitrogen, while bioswales are best for phosphorus and bacteria. Both wet swales and bioswales can also treat heavy metals. The type of swale chosen should consider site constraints, climate, and available funding. Proper siting, investigation, and maintenance planning are crucial for long-term performance. More research is needed to optimize design parameters for all swale types, especially wet swales.