Municipal Separate Storm Sewer System (MS4)

The objective of this Stormwater Management Plan (SWMP) is to develop a program with which the City of Killeen can reduce the discharge of pollutants to the Maximum Extent Practicable (MEP). This program was developed to ensure that the City meet the State program requirements and utilize current activities to address issues that are important and is economically feasible.

What is a MS4 (Municipal Separate Storm Sewer System)?

Municipal separate storm sewer systems (MS4s) consist of a conveyance or system of conveyances, including roads with drainage systems, streets, catch basins, curbs, gutters, ditches, human-made channels, or storm drains. 

Polluted stormwater runoff is commonly transported through municipal separate storm sewer systems (MS4s), and then often discharged, untreated, into local water bodies.

An MS4 is a conveyance or system of conveyances that is:

  • owned by a state, city, town, village, or other public entity that discharges to waters of the U.S.,
  • designed or used to collect or convey stormwater (e.g., storm drains, pipes, ditches, streets, curbs and gutters),
  • not a combined sewer, and
  • not part of a sewage treatment plant, or publicly owned treatment works (POTW).

What is required of a MS4?

The MS4 is required to develop a Stormwater Management Plan (SWMP) that develops ordinances and other guidelines that follow 6 Minimum Control Measures (MCM) these MCMs are designed to ensure that harmful pollutants do not enter our water ways. 

The 6 MCMs are: 

  • MCM 1: Public Education, Outreach, and Involvement
  • MCM 2: Illicit Discharge Detection and Elimination
  • MCM 3: Construction Site Stormwater Runoff Control
  • MCM 4: Post-construction Stormwater Management in New Development and Redevelopment
  • MCM 5: Pollution Prevention and Good Housekeeping for Municipal Operations
  • MCM 6: Industrial Stormwater Sources (- only if your MS4 serves a population more than 100,000)

The items listed are part of a Permit issued by the Texas Commission on Environmental Quality (TCEQ), that is required by each City within an Urbanized area that services more than 20,000 people. As part of our Permit with TCEQ we are required to post a copy of our Stormwater Management Plan and Annual Reports.