As both an MS4 community and part of the Milwaukee River Basin, the city of Cudahy, Wisc., is required to remove suspended solids and phosphorus from storm water runoff. Additionally, the city is committed to implementing green infrastructure practices into public works projects, so when the city was tasked with replacing an alley and a couple of parking lots, they were introduced to air-cooled blast furnace slag. After an ecotoxicity test showed little impact, and a way to work around a residential area was discovered, the city chose to use a permeable articulating concrete block to capture and transfer storm water under the alley and one parking lot. The high-performance biofilter, FocalPoint, was used for the second parking lot. To document the capability of the systems, officials have implemented a three-year monitoring program of the discharge for both project areas.