Phone: 847-816-6800

Hours: Mon-Fri, 8:30 am - 4:30 pm

An MS4 entity owns or operates a system for collecting and conveying stormwater. The purpose of the MS4 program is to maintain and benefit water quality in creeks streams and waterways by reducing pollutants in stormwater runoff.

The MS4 program is an unfunded federal mandate. It is the result of the 1987 amendments to the Clean Water Act, commonly referred to as the Water Quality Act of 1987. In these amendments, Congress mandated that the U.S. Environmental Protection Agency (USEPA) address non-point source pollution associated with stormwater runoff. In response to the Congressional action, the USEPA developed the MS4 program to permit the discharge of the stormwater from the MS4s. In essence, EPA defined urban stormwater (previously considered a non-point source) as a point source with numerous physical locations (or points) of discharge.

The MS4s are permitted under the National Pollutant Discharge Elimination System (NPDES) program through the Illinois Environmental Protection Agency (IEPA). MS4 permits are granted in five-year cycles at the end of which the permit must be renewed. The NPDES permit was granted in 2003, and was renewed in 2009.

The MS4 entities are required to develop a Stormwater Management Plan (SWMP), and to implement the following six Minimum Control Measures to reduce polluted stormwater runoff:

  • Public Education and Outreach
  • Public Involvement and Participation
  • Illicit Discharge Detection and Elimination
  • Construction Site Runoff Control
  • Post-Construction Stormwater Management
  • Pollution Prevention and Good Housekeeping at Municipal Operations

Why is the program necessary?

As it flows, stormwater runoff collects and transports pollutants to surface waters. Although the amount of pollutants from a single residential, commercial, industrial or construction site may seem unimportant, the combined concentrations of contaminants threaten our lakes, rivers, wetlands and other water bodies. Pollution conveyed by stormwater degrades the quality of drinking water and damages the habitat of plants and animals that depend on clean water for survival. Pollutants carried by stormwater can also affect recreational uses of water bodies by making them unsafe for wading, swimming, boating and fishing.

What is the Township doing to comply with the permit requirements?

  1. The Township has developed a Stormwater Management Plan that outlines the Township’s plan for compliance with the six Minimum Control Measures, which should result in significant reduction in pollutants discharged into receiving waters.
  2. The Township implements an Illicit Discharge Detection and Elimination program that includes inspection of the Township’s outfalls, streams and detention basins each year.
  3. The Township conducts annual water quality testing at upstream and downstream locations in the watershed.
  4. The Township implements a program that reduces pollutant runoff from Township operations.

The Township is committed to improving water quality through better management of stormwater runoff. Every resident and business owner can participate in the stormwater program by reducing or preventing pollutant runoff from their own property and by reporting any non-stormwater discharges into the Township’s drainage system.

How can I help reduce stormwater pollution?

Everyone can help reduce water pollution through stormwater runoff. Simple things such as washing our cars on a grassed area where the detergents will soak into the ground instead of running along the driveway and street into an inlet that will carry it all the way to a lake or stream can make a difference. Use the correct amount of fertilizer for your plants when needed so that the excess is not washed off, creating algae blooms in nearby lakes and ponds. If you must use pesticides, search for an environment-friendly brand. Recycle motor oil, paint and other hazardous chemicals. Never dump such materials down the drain or into the storm system. Dispose of trash and yard waste in proper ways so that they do not get washed into our lakes and streams. Always pick up your pet's waste or harmful bacteria can get into our water! There are many such activities that can make a difference and preserve our lakes and streams for future generations.

Pollutants: Their Sources and Impacts

A pollutant is any substance that can harm living things. Pollutants commonly found in the Township waterways include:


Source: Construction sites and other non-vegetated lands.

Impacts: Uncontrolled soil erosion can result in excess sediment that clogs catch basins, storm sewers and detention basins, leading to higher maintenance cost and flooding. As it settles, sediment can smother fish eggs and bottom dwellings organisms, and destroy aquatic habitat. Suspended sediment can lower the transmission of light through water and can negatively affect aquatic animals. Other pollutants can attach to soil particles. When sediments wash off the ground into waterways they carry these pollutants with them.


Sources: Septic systems, lawn fertilizers, animal waste, cleaning products, plant debris and eroded soil.

Impacts: Phosphorous and nitrogen can over stimulate aquatic weed and algae growth. As they decay, excess weeds and algae use oxygen in the water, which is needed by fish and other aquatic life.

Toxic Compounds

Sources: Toxic substances include vehicle fluids, solvents, lawn herbicides and pesticides, paints and metals such as chromium, copper and mercury.

Impacts: Toxins can accumulate in the aquatic food chain, as one larger organism eats many smaller ones that have been contaminated. Even in very small concentrations, oils and other toxic substances can harm aquatic plants and animals.

Litter and Debris

Sources: Grass clippings, leaves and litter generated by careless disposal practices.

Impacts: Litter and leaves that wash into storm; sewers can clog detention basin inlets and outlets, and eventually pollute streams and rivers. Excessive leaves and other organic materials decompose and lower the amount of oxygen available to aquatic life.\


Protect Our Waterways

In a way, we all live on a river. Water that enters our storm drains flows directly into a stream or river untreated, along with everything that rainwaters carries away from our streets: trash, leaves, grass, fertilizers, pet wastes, etc. Reducing pollutants from rainstorm runoff is one of the biggest hurdles to keeping our river clean.

During the fall, it is especially important to keep leaves out of the storm inlets. In addition to clogging drains and causing backups, leaves that enter the storm drains decay in the water and rob fish of vital oxygen. Follow these steps to give our waterways a hand; you’ll also reduce the risk of flooding on your street.

  1. Compost yard waste. The next time you mow, mulch the leaves while cutting the grass. They’re the best nutrients.
  2. Wait until the last minute. If you have your leaves picked up by a community leaf collection program, rake the leaves into the street just prior to your scheduled pick-up day. Should it rain, leaves won’t enter the storm drain inlets and waterways as easily if they are raked and stored on your lawn extension for as long as possible.
  3. Stay out of the gutter. If your community does allow you to sweep leaves to the street for collection, be sure to keep leaves out of the gutter. There should be at least a one-foot space between the curb and your leaves for the storm water to run into the gutter. This will reduce the risk of flooding in your area.
  4. Keep inlets clear. Reduce the risk of flooding and help protect the environment by removing accumulated debris from catch basin grates. Don’t deposit yard or pet wastes into catch basins.

A Citizen's Guide to Monitoring Stormwater

Ten Ways Homeowners Can Improve the Quality of Stormwater Runoff

Need fertilizer? Go slow!

Year 21 Water Quality Report for 2023

20130922 NOI Submittal

MS4 Report Annual Presentation - May 10, 2022

Year 7 Full Submittal

Year 8 Annual Report

Year 9 Annual Report

Year 10 Annual Report

Year 11 Annual Report

Year 12 Annual Report

Year 13 Annual Report

Year 14 Annual Report

Year 15 Annual Report

Year 16 Annual Report

Year 17 Annual Report 

Year 18 Annual Report 

Year 19 Annual Report

Year 20 Annual Report

Year 21 Annual Report

Libertyville Township Stormwater Management Program Adopted November 2009

Illinois EPA General NPDES Permit No. ILR40

2019 Outfall & Basin Inspection Report

359 Merrill Court, Libertyville, IL 60048 | Phone: 847-816-6800 | Email: 

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