A storm drain system (10) contained in the ground (36) contains a standpipe (12) having a bottom section (18) having perforations (20) where a porous pavement (22) surrounds the top portion of the standpipe (12), where, beneath the porous pavement is a substructure of coarse aggregate, all surrounded by a non-porous base material (34), such as concrete, where a storm drain (28) connects to the standpipe by a top outlet pipe (30), where water (38, 40) and liquid impurities (42) are separated from storm water runoff by a non-perforated section of the standpipe.