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ECAR Fact Sheet for Michigan
Wastewater Discharges

Self-Audit Checklist
Best Management Practices
Related ECAR Fact Sheets
Other Relevant Resources


The following fact sheet was prepared by the ECAR Center staff. Once prepared, each ECAR Center fact sheet undergoes a review process with the applicable state environmental agency(ies). You can check on the status of the review process here. Please read the disclaimer on the status page. While we have tried to present a summary of the essential information on this topic, you should be aware that other items, such as local regulations, may apply to you.

What You Need to Know

You are responsible for contamination caused by any waste, including wastewater, generated from your business. Improper discharge of wastewater can result in both soil and water contamination and potentially cost your business a great deal of cleanup costs and fines. These discharges may have a negative impact on fish, wildlife and drinking water.

This fact sheet identifies wastewater types, disposal options, permitting, and record keeping requirements.


Regulated wastewater falls into three basic categories:

  1. Sanitary wastewater This is water from your restrooms, break-rooms and sinks. It is not wastewater from washing tools or pouring waste auto fluids down the drain.
  2. Non-sanitary or industrial wastewater This is the wastewater that results from your business activities that might contain one or more pollutants. It includes wastewater resulting from radiator flushing, tool and engine cleaning, discharges from aqueous cleaning, water from steam cleaning or equipment wash down, water used for floor cleanup in dismantling areas (e.g., mop water) or non-contact cooling water and precipitation collected in secondary containment areas.
  3. Stormwater This is water from rainfall and snow melt runoff. See the ECAR Stormwater fact sheet.

Your disposal options depend on the type of wastewater your business generates and the location of your company. These options include:

  • Publicly Owned Treatment Works (POTW, also known as municipal wastewater treatment plants or sanitary sewer systems).
  • Permitted and Registered Hazardous or Liquid Industrial Waste Transporters (for liquid waste that can not be discharged in any other fashion).
  • Surface Water Discharge (includes direct discharge to a lake, river, or stream and indirect discharge via a storm sewer, drain or ditch). A permit is required for this type of discharge.
  • Groundwater Discharge (includes septic systems) A permit is required for this type of discharge.

POTWs Wastewater discharged to a POTW is regulated by the local sewer authority. Contact your local sewer authority to determine if your waste will be accepted by their facility. In some cases, you may be required to conduct "pretreatment" (oil/water separation, removing solids, chemicals, etc.) before discharging your wastewater to them. Also review with your local sewer authority whether there are any monitoring, record keeping, and/or sampling requirements.

Sanitary wastewater can be discharged to a municipal sewer system. Many municipal systems also accept some non-sanitary wastewater with prior approval. Generally, you will be required to fill out an application detailing what wastes you are requesting permission to discharge. Your sewer authority will review the application and notify you if you can or cannot discharge the waste to their POTW.

Hazardous or Liquid Industrial Waste Transporters Wastewater that is not discharged into a POTW system must be taken to a recycling or disposal facility if you do not have a discharge permit. Before you haul wastewater or have it hauled off-site. you must perform a hazardous waste determination. This may involve getting it tested by a laboratory. Keep test records or other documentation that supports your determination for at least 3 years from shipment. If the wastewater is "hazardous" you must manage it as hazardous waste. For more information, see the Hazardous Waste Plain Language Guide. If the wastewater is non-hazardous, it is managed as liquid industrial waste in Michigan.

Surface Water Discharge Discharges to surface waters are regulated under the Clean Water Act. Discharges to local storm sewers, ditches or other conveyances are also regulated when they discharge to waters of the state. You are required to obtain a National Pollutant Elimination System (NPDES) permit issued by the MDEQ Water Bureau. An NPDES permit requires you to regularly monitor your discharge and submit reports to the Water Bureau.

Groundwater Discharge All discharges to the groundwater must be authorized by DEQ or the local health department. Discharges that go to septic systems or directly onto the ground are considered groundwater discharges. Sanitary wastewater can be discharged to an approved septic tank system authorized by the local health department. Discharges of non-sanitary wastewater to groundwater must be authorized by the DEQ Water Bureau. Discharge of floor drain waste is not allowed because it is difficult, if not impossible to properly characterize the waste.

Reporting. The state of Michigan requires that businesses that meet the annual wastewater reporting criteria to submit either an abbreviated wastewater report or a full wastewater report.. The report includes the quantities of critical materials used in and incidental to the businesses manufacturing processes, including by-products and waste products. You must submit the report by August 1 each year.

Businesses that have wastewater discharge permits also have reporting requirements as identified in their permit.

Links to the Regulations and Forms. Use the following links to view the regulations and permit forms pertaining to wastewater.

Industrial Pretreatment

Michigan Annual Wastewater Reporting (AWR) Program

Groundwater Discharge Permits

NPDES Permits

Michigan's Natural Resources and Environmental Protection (Act 451), Part 121 regarding Liquid Industrial Waste

Michigan's Natural Resources and Environmental Protection (Act 451), Part 111 regarding Hazardous Waste Management and administrative rules

Self-Audit Checklist

When an inspector comes to your facility, there are certain things he or she checks to see if you are in compliance with environmental regulations. It makes good sense for you to perform a "self-audit" and catch and correct problems before they result in penalties. Also, there are some compliance incentives associated with self-audits (see Audit Policy Page). Use the following list to audit your wastewater management activities.

  1. Does your facility discharge industrial wastewater? Are the discharges authorized by a permit? Are you meeting monitoring and reporting requirements identified in the permit? Check all uses of water and steam within the industrial areas of your facility. Determine where wastewater is generated and discharged. You must have a permit to discharge wastewater to the waters of the state. You must have prior approval before discharge non-sanitary wastewater to a POTW.
  2. Is oil or solvent discharged to the sewer? Federal and state laws prohibit the discharge of oil or flammable solvents to the sewer system. These are regulated wastes that must be properly disposed of.
  3. Have you filed an annual wastewater report? Under the AWR program, most facilities that discharge wastewater must file an annual report with MDEQ.

Best Management Practices (BMPs)

Most regulations tell you what you have to do to be in compliance, but they don't explain how to do it. That's where "best management practices" come into play. BMPs are proven methods that help you to get into compliance and stay there. The following BMPs are recommended for wastewater management.

  • Limit water use and the volume of water discharged through conservation methods and by reusing water whenever possible.
  • Train employees to use water efficiently.
  • Don't use water for cleaning floors and equipment unless absolutely necessary. Use dry cleanup methods for spills.
  • Post signs at all floor drains and sinks in industrial areas of your facility to discourage employees from using the drains to dispose of oil, other vehicle fluids, solvent, paint or similar liquids. Review these rules with your employees.
  • Use only non-toxic soaps to clean floors and vehicles instead of hazardous materials.
  • If you have floor drains at your facility that are not in use, have them capped or plugged to prevent misuse or accidental discharges.
  • Prevent drips and spills from reaching the floor.
  • Check your floor drains and make certain you know where they discharge.
  • Setup and use a maintenance schedule for inspection and cleaning of floor drains, oil/water separators, traps, etc.
  • Never have floor drains where hazardous materials are stored.
  • If your wastewater is nonhazardous, you may want to purchase evaporating equipment to evaporate your wastewater. It should be noted that evaporators may require an air permit or registration, and evaporator bottoms may be considered a hazardous waste.
  • Don't use degreaser solvents to clean engines. Most engine degreasers are hazardous and should not be discharged to a POTW. Even if you use nonhazardous degreasers, the oil and grease concentration in the spent degreaser may exceed the limit allowed by your sewer authority.


  1. For Annual Wastewater Report (AWR) questions, contact 517-373-2461.
  2. For questions regarding the Industrial Pretreatment Program, contact your local sewer authority or MDEQ Water Bureau District Office.
  3. For storm water questions, contact MDEQ at 517-241-8993 or MDEQ Water Bureau District Office.
  4. For NPDES permits, contact MDEQ Water Bureau District Office
  5. For sanitary wastewater discharges into septic systems, contact local health department
  6. For all other wastewater groundwater discharges, including into septic systems, contact MDEQ Water Bureau District Office
  7. For questions about hazardous waste, liquid industrial waste, and transporting wastewater and disposal off-site, contact Environmental Assistance Center at 800-662-9278 or MDEQ Waste and Hazardous Materials Division District Office

Related ECAR Fact Sheets
  1. Stormwater
  2. Aqueous Cleaning
  3. Floor Drains
  4. Septic Tanks and Disposal Wells

Other Relevant Resources
  1. Frequently Asked Questions regarding Annual Wastewater Reporting, prepared by DEQ.
  2. List of permitted and registered waste transporters


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