Municipal Separate Storm Sewer System (MS4)

The City of Lakeway was originally issued authorization under the Texas Pollutant Discharge Elimination System (TPDES) Small MS4 General Permit administered by the Texas Commission on Environmental Quality (TCEQ) in 2015. Authorization under this permit is required for all operators of a small municipal separate storm sewer system (MS4) that discharges stormwater to surface waters of the state. A primary requirement of this permit is the development of a Stormwater Management Plan (SWMP) which includes plans for the implementation of control measures that serve to reduce pollution in stormwater to the maximum extent practical. Per the requirements of the permit, the city plans to implement best management practices (BMPs) detailed under the following categories of Minimum Control Measures (MCMs):

  1. Public Education, Outreach, and Involvement
  2. Illicit Discharge Detection and Elimination
  3. Construction Site Stormwater Runoff Control
  4. Post Construction Storm Water Management in New Development and Redevelopment
  5. Pollution Prevention and Good Housekeeping for Municipal Operations

What is “Stormwater”?

The term “stormwater” refers to precipitation resulting from a storm event. Impervious surfaces such as rooftops, driveways, and roads prevent stormwater from infiltrating into the ground. When a storm event occurs, the portion of water that is not absorbed into the ground becomes what is known as “stormwater runoff”.

Why should you care about stormwater runoff?

Stormwater runoff picks up and carries a wide variety of pollutants and debris – such as sediments, fertilizers, pesticides, pet waste, trash, and automotive fluids – which then flow into storm drains or channels and eventually empty into the waterways that we use for recreation and drinking water. Unlike household wastewater (from sinks, toilets, and showers), stormwater is not filtered or treated at a wastewater treatment plant and is conveyed directly into nearby lakes, rivers, and creeks.

What are common sources of stormwater pollution?

While there are many different pollutants that are carried by stormwater, typical stormwater pollution may be divided into three general categories:

  1. Natural – organic material such as leaves, grass clippings, and soil sediments.
  2. Chemical – items such as detergents, fertilizers, oil and grease.
  3. Litter – plastic bags, drink containers, wrappers, and cigarette butts.

How can you help minimize stormwater pollution?

stormwater pollution

Illicit Discharge

With few exceptions, an illicit discharge is any release that is not composed entirely of stormwater into an MS4 conveyance or directly into a waterbody. Examples of illicit discharges include chemicals, hazardous materials, petroleum products, sediments, grass clippings and trash. To report a suspected illicit discharge, please contact Lakeway Code Compliance at 512-314-7550.

Please note that the following are NOT considered illicit discharges:

  • Dechlorinated swimming pool water
  • Individual residential car washing
  • Runoff from lawn landscaping and irrigation
  • Discharges or flows from emergency fire fighting activity

For general stormwater information, please contact:

Environmental Coordinator, Kyle Honnerlaw