Are you claiming buildings to be permeable? Most just shed water away from them and often directly to a road or parking lot. A bulding would need a dedicated stormwater plan, such as a retention pond, to reduce its impacts with impermeable surfaces in urban environments.
Roads and parking lots are typically the main impermeable surfaces.
I’m including parking garages as parking lots.
Are you claiming buildings to be permeable? Most just shed water away from them and often directly to a road or parking lot. A bulding would need a dedicated stormwater plan, such as a retention pond, to reduce its impacts with impermeable surfaces in urban environments.