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The City of Corpus Christi operates a Municipal Separate Storm Sewer System, also called an MS4. An MS4 describes a system in which the storm water runoff does not connect with a wastewater collection system or treatment plant. 

In short, Storm Water and Wastewater are two separate drainage systems. The Storm Water drainage system is a system of roadside ditches, underground pipes and culverts, and major collector ditches which channel rainfall runoff untreated directly to our bays.The Wastewater system is a network of underground pipes to transport wastewater to treatment plants.

There are two basic methods by which rainfall runoff is collected from adjacent properties. In areas where there is no curb and gutter, the streets are elevated above the surrounding ground level, and runoff from the adjacent properties and street pavement is collected by the roadside ditches which in turn run into the major ditches. In areas where curb and gutter is installed, the street elevation is below the surrounding land. The curb and gutter, as well as the street, collects the runoff and carries it to curb inlets. The inlets are connected to an underground pipe system which channels the runoff to the major ditches.

The system, whether it be ditches or pipes, is designed to accommodate the runoff from a storm of a specific intensity (how fast the rain falls) and duration (how long the storm lasts). If a storm event exceeds the design parameters, the excess runoff can not be accommodated by the system and is "stored" in the roadside ditches or, in the case of a curbed street, in the street itself. Once the event has passed, the water is carried off through the system in a relatively short time.