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ECAR Fact Sheet for Wisconsin
Septic Tanks and Disposal Wells

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

There is a simple rule for determining when it is OK to put industrial wastewater into a septic system - never.  You can dispose of "sanitary wastes" from ordinary lavatory use or hand washing in a septic field only if the wastewater has not been contaminated with any water from an industrial operation.

Some yards may have shallow wells or cesspools that have been used for disposal of industrial wastewater.  It is now illegal to create such systems, and existing systems need to be sealed or closed.  This fact sheet will help you check whether your existing wastewater disposal practices are in compliance with current rules.


This fact sheet explains the regulations applicable to septic tanks or other forms of disposal wells used at auto recycling facilities for disposal of vehicle fluids or industrial wastewater. These methods of disposal are referred to as "motor vehicle waste disposal wells." They are regulated under federal and state Underground Injection Control (UIC) regulations that protect drinking water supplies.

Motor vehicle waste disposal wells are floor drains or sinks in service bays that are tied into a shallow disposal system. Most commonly, these shallow disposal systems are septic systems or dry wells, but any underground system that receives motor vehicle waste would be considered a motor vehicle waste disposal well. A variety of names are used to describe shallow disposal systems including: cesspools, catch basins, sink holes, underground vaults, or drain tanks, to name a few. This regulation does not apply to a system where the final disposal of the wastewater is to a holding tank.

Automotive recyclers must adhere to the following federal rules for motor vehicle waste disposal wells:

  • New motor vehicle waste disposal wells are banned nationwide as of April 5, 2000.
  • Motor vehicle service facilities with existing floor drains connected to a POWTS that includes a soil absorption component that were constructed prior to April 5, 2000 will have from five to seven years to come into compliance with this federal rule. Options that may be considered for these systems include sealing shut the floor drains to eliminate any discharge, connecting to a holding tank or connecting to a public sanitary sewer. If these options are not practicable, the service building owner may apply for a Wisconsin Pollutant Discharge Elimination System (WPDES) permit from the DNR. This permit would require compliance with groundwater standards to prevent any harmful pollutants from entering the disposal system.

If you have an existing septic tank, you should register with the Wisconsin Department of Natural Resources (DNR). See link below.

The only permissible use for septic systems is disposal of sanitary sewage, which includes the water coming from lavatories/washrooms, showers, drinking fountains, etc.

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

Wisconsin DNR - Septic Tank Registration Form

Federal Rules for Motor Vehicle Waste Disposal Wells

Class V Well Pre-Closure Notification Form

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 septic tank or underground well.

  1. Does your facility discharge vehicle fluids or related industrial wastewater to a septic tank or similar system? Does a permit authorize the discharges? 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 or written authorization for all industrial wastewater discharges. Use of a septic tank or similar system is not a viable option.

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 septic tank management.

  • Check your sinks and floor drains in the shop to make certain you know where they discharge.
  • Cap or plug any floor drains connected to a septic tank.
  • Do not put other fluids like oil, solvents, paints or chemicals into a floor drain. This could contaminate your property and expose you to large fines and clean up costs.
  • Think about installing an emergency shut-off on the drain pipes to prevent accidental spills from entering the sewer.
  • Train employees on the importance of preventing any vehicle fluids or other industrial wastes from entering a septic tank or well.
  • Post signs at sinks connected to your septic tank system to remind employees not to discard any wastes into the sink.


  1. For more information, contact Wisconsin's DNR Auto Salvage Sector Resource Specialist at 715-831-3263, or contact the WDNR Regional Office in your area. For northern Wisconsin, call 715-635-2101 or 715-365-8900; West Central Wisconsin, call 715-839-3700; Northeast Wisconsin, call 920-492-5800; Southeast Wisconsin, call 414-263-8500; and, for South Central Wisconsin, call 608-275-3266.

  2. All spills should be immediately reported using Wisconsin's 24-hour toll free hotline at 800-943-0003. If you discover a discharge through analysis of soil or water, use the Hazardous Substance Release Fax Notification Form.

Related ECAR Fact Sheets

  1. Floor Drains
  2. Stormwater
  3. Wastewater

Other Relevant Resources

  1. What Should I Know About Motor Vehicle Waste Disposal Wells?


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