It is a common scenario that the street of Bahir Dar will be flooded by the stormwater runoff whenever there is rainfall in the city. This is partially due to inadequate stormwater drainage infrastructure and the flat terrain of the city. However, the increased impervious surfaces also worsen the problem. This created difficulties in both pedestrian and vehicular movement. So it is essential to solve this problem. Due to developments in concrete technology, it is possible to use porous concrete that resembles the natural porous land in infiltrating the runoff stormwater, and that gives durable, aesthetically beautiful, and better surface texture than the natural earth surface. However, to do mix proportioning of the porous concrete relationship between the local aggregate properties and porous concrete performance shall be known. The main objective of this study is to determine a relationship between aggregate size and gradation on porous concrete performance. This research included a series of laboratory tests carried out on one aggregate source, sixteen aggregate gradation, and two hundred forty test specimens. Aggregate properties (such as dry rodded density, void content, uniformity coefficient, abrasion resistance, and gradation) and porous concrete performance (such as unit weight, compressive strength, porosity, permeability, and abrasion loss) were determined. The correlation between these parameters was developed, discussed, and presented. As the results revealed, generated higher compressive strength from the blended gradations with higher uniformity coefficient values. In general, the single-sized aggregates mixes were on the lower end of the compressive strength scale, but it is on the higher end of porosity and permeability scale. However, equal proportion binary blend mix (#450%#1250%) and equal proportion ternary blend mix (#433%#933%#1233%) produced optimum compressive strength and permeability for the production of porous concrete. From the tested aggregate size and gradations and the developed relationships in this study, it was found that aggregate properties influence the performance of porous concrete.