What is stormwater?

Stormwater runoff is generated from rain and snowmelt that flows over land or impervious surfaces, such as paved roads, parking lots or building rooftops, that does not soak into the ground. Stormwater flows into drains that take it directly to nearby lakes, rivers and streams.

To learn more about stormwater and how it is managed at the national level, click here. For more information about municipal stormwater programs in Michigan, click here.

Stormwater is NOT treated before it reaches our waterways. Therefore it is extremely important to follow some simple best management practices (BMPs) in order to minimize the pollution that reaches our lakes, rivers and streams. The photos below illustrate how our actions can impact stormwater runoff.

What is an MS4?

Municipal Separate Storm Sewer System -Stormwater runoff is transported through Municipal Separate Storm Sewer Systems (MS4s) and then discharged untreated into local waterbodies. The MS4 is a conveyance or system of conveyances that is owned by a municipality that discharges to waters of the United States that is not a part of a combined sewer or sewage treatment plant. To prevent harmful pollutants from entering the waterways through MS4s, certain municipalities are required to obtain permits and develop stormwater management programs. More information can be found here.  


  • Best Management Practices (BMPs) - Structural, vegetative or managerial practices used to treat, prevent or reduce water pollution in stormwater runoff
  • Point Source Pollution - The U.S. Environmental Protection Agency (EPA) defines point source pollution as “any single identifiable source of pollution from which pollutants are discharged, such as a pipe, ditch, ship or factory smokestack” (Hill, 1997). Point sources receive a wasteload allocation (WLA) and include all sources subject to regulation under the National Pollutant Discharge Elimination System (NPDES) program, such as wastewater treatment facilities, stormwater discharges, and concentrated animal feeding operations *(CAFOs).
  • Nonpoint Source (NPS) Pollution - unlike pollution from industrial and sewage treatment plants, nonpoint source pollution comes from many diffuse sources. NPS receive a load allocation (LA) which include all remaining sources of the pollutant as well as natural background sources.

Stormwater BMPs:

  • Wash your car at the car wash or on the grass (NOT on the driveway!)
  • Keep stormdrains clear of debris and trash
  • Use phosphorus free fertilizer (or don't use any)
  • Shovel first, salt second (or not at all)
  • Do not put anything in a storm drain (only rain in the drain)

Stormwater Runoff

Pollution Solutions

As stormwater flows off driveways and streets, it picks up and carries most of the items in its path. Things such as grass clippings, driveway salt, fertilizer, pet waste, trash, and more! Read on to learn about some common sources of stormwater pollution and ways that you can prevent pollution in your lakes, rivers, and streams.


Proper Pet Waste Disposal


Pet waste that is not properly disposed of can lead to many unwanted things in our waterways, such as E. coli, parasites, and other harmful bacteria. When stormwater runs over pet waste, it carries it to the nearest catch basin and then flows directly into the nearest waterway. E. coli is bacteria that lives in the lower intestines of warm blooded animals, like dogs and people. It is also present in waste. When E. coli gets into our water where we fish and swim, it pollutes it and can make us sick. To properly dispose of pet waste you should bag it and dispose of it in a nearby trash receptacle.

Pledge to pick up your pets waste and receive a FREE pet waste bag dispenser!

Must include full mailing address in order to recieve dispenser.
I pledge to be environmentally responsible by keeping my dog on leash and on the trail in natural areas and scooping and properly disposing of pet waste.
Pet Waste Pledge and Bag Dispenser

Clean Green Lawn Fertilizer N P K

Lawn Care & Phosphorus Free Fertilizer

Proper Grass Height Three Inces

People love their yards, and they often do quite a bit of work to care for them. They mow their grass, water, weed, and fertilize their yards to keep them looking green and uniform all summer long. Another common stormwater pollutant is phosphorus which can be found in many common lawn fertilizers. Too much phosphorus can create harmful algal blooms in water bodies which can make people, fish, and other animals sick if they swim in, or touch the water. Fertilizers have three main ingredients, Nitrogen (N), Phosphorus (P), and Potassium(K). However, phosphorus is not actually needed to grow a healthy lawn. Alternatively, you can keep grass 3 inches in height. This height will allow the grass to soak up more water, reducing the stormwater runoff from the lawn, which that means less watering and using less or no fertilizer. Using phosphorus-free fertilizer (where P=0) is another good practice.

Shovel First Salt Less

Snow, Ice, & Salt

dirty snow on pavement

During winter time we often shovel and throw salt on our driveways and roads to reduce icing and make it safer to drive on. Many don't realize however, that all the salt, dirt, and sand that is collected in that snow and on those driveways and streets, ends up flowing into the catch basins and into our water bodies, polluting them. Dirt and sand build up in the bottoms of the catch basins, causing them to fill and no longer accept stormwater, which in turn can flood streets. The sand and dirt that is suspended in the water ends up in the water ways and creates sediment build-up which displaces fish and other aquatic life. The salt that flows into the river is almost impossible to remove and makes the water uninhabitable for some marine life. Large snow piles formed over the winter collect dirt, sand, and trash. When the snow finally melts, it carries all of that into the catch basin. So, what can we do? We can shovel our driveways and roads prior to salting them. This will make it so they require less, if any, salt. We can move snow piles into grassy or other vegetated areas so that the water will be absorbed into the ground and recharge as ground water.

Shovel first, salt second (or better, never!)

Car Wash

When washing your car, choose a car wash facility or wash over your lawn or other permeable surface. Car wash facilities have overflow systems where the soapy water will enter the sanitary system and is then treated before entering waterways or being reused. Grass will soak up and filter pollutants from car wash runoff before entering the storm drain that leads directly to the nearest lake, river, or stream.

Sign the car wash pledge today and receive a free LGROW car wash shammy in the mail!

I hereby pledge to be environmentaly responsible by washing my car at a commercial car wash OR on the grass, where soapy water, grease, and dirt can't make their way to storm drains, rivers, or lakes.
Street, City, State & Zip (required to receive free car wash shammy

Green Infrastructure

Green infrastructure is the practice of infiltrating stormwater by use of natural systems in order to reestablish a healthy water flow. These systems allow for the infiltration of stormwater before it is released into conventional storm and sewer system, protecting our lakes, rivers, and streams from harmful pollutants. These practices lead to vital community features such as public parks, forests, rivers, wetlands and lakes. Using these natural systems to treat stormwater results in cleaner water, improved air quality, healthy wildlife habitats, and safe recreation sites. Urban areas are beginning to face new state and federal regulations to clean up rivers and reduce stormwater runoff. With green infrastructure these communities can create comprehensive plans, determine new development areas, and redevelop other areas in need and will improve local communities and attract good jobs. 

There are many different types of green infrastructure that range from simple rain barrels all the way to porous pavement. If you are interested in installing green infrastructure on your property visit Grand River Rainscaping Program: Treating Stormwater Naturally for more information

The vision of green infrastructure in the Lower Grand River Watershed is shown on the Natural Connections map below.
*Note - This is a very large PDF, click the image below for the full PDF document then zoom in to see clearly.

Click for PDF 

Click for PDF 



Illicit Discharge

Illicit Discharge No Dumping

Illicit Discharge is any discharge (or seepage) to the separate storm water drainage system that is not composed entirely of storm water or uncontaminated groundwater.

Illicit Connection is a physical connection to a separate storm water drainage system that primarily conveys illicit discharges into the system and/or is not authorized or permitted by the local authority (where a local authority requires such).

Illicit Discharge Warning Signs

  • Dry Weather Flow is noted when it has not rained for at least 72 hours and the storm drain has flow or the drain shows signs of intermittent flow (staining, odor).
  • Sanitary Sewage may be present if there is black staining inside the drainage pipe; visible evidence of sanitary waste, such as toilet paper; or opaque or gray water.  Sewage may originate from septic tank overflow pipes or improperly dumped travel trailer waste. 
  • Suds may be harmful to fish because suds deplete oxygen levels in the water.  Suds often enter lakes and streams as a result of improperly connected car washes or washing machines. 
  • Oil/Gas is recognized as a sheen on the water. Natural sheens may be differentiated from an oil/gas sheen by swirling the sheen around in the water. If it re-attaches, the sheen is oil/gas. Natural sheens will remain separated. Oil/Gas enters waterbodies via storm water runoff (spills while topping off at gas stations, oil leaks on pavement, etc.) and illegal dumping.

Illicit Discharge Reporting

To protect the quality of our streams and public health, please report sources of pollution you witness along the roadside or at rest areas and roadside parks, including:

  • Dumping waste/oil or other vehicle fluids
  • Suspicious pipes outletting to ditches
You can do this anonymously by calling the pollution emergency alerting system (PEAS) hotline at: 800-292-4706 or for community specific reporting click here

Please, Report Illegal Discharges!

The information on this page was originally from Michigan Department of Transportation (MDOT) and can be found here.

Only Rain in the Drain