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ECAR Fact Sheet for Colorado
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

Wastewater is often generated by operations such as the rinsing of parts, and the washing down of engines or dirty tools. If water becomes mixed with oil, antifreeze, solvents, or other liquids, it is important that it be properly treated and contained prior to discharge. If your wastewater is currently just going down an unregulated drain, you've got a problem.  Even if your activities have gone unnoticed for years, there is an increasing chance that you will be inspected.  The federal EPA and the states are starting to look much more carefully at sources of water pollution that have so far remained unidentified, and they have (rightly or wrongly) decided that auto recyclers are a significant problem area.

You will almost certainly need separate permits both for stormwater runoff (see the ECAR Stormwater fact sheet) and for any industrial wastewater that you generate.  This page will give you an overview of how to handle your industrial wastewater.


This fact sheet addresses wastewater discharges other than stormwater, which is covered by a different fact sheet. Wastewater from salvage yards can be subdivided into two main types:

  • "Sanitary wastewater" includes the water coming from lavatories/washrooms, showers, drinking fountains, etc.
  • "Industrial wastewater" includes the water going into floor drains in areas such as dismantling, 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 water from any other sources where it comes into contact with dismantled parts or equipment.

Colorado's regulations on wastewater generally reflect those established under federal law. Sanitary wastewater can be discharged to a city sewer system, however, most local governments require businesses to obtain a discharge permit. Sanitary wastewater cannot be discharged to a stream, pond, or wetland without having a special permit. If you have questions regarding sanitary wastewater, contact your local sewer authority or the Colorado Department of Public Health and Environment (CDPHE).

Industrial wastewater is regulated differently than sanitary wastewater. If you combine sanitary and industrial wastewater, then the mixed wastewater is regulated like industrial wastewater. All industrial wastewater discharges are regulated by federal and state regulations and in most cases, also by local regulations.

Permits. A National Discharge Elimination System (NPDES) permit from the CDPHE is required to discharge industrial wastewater directly into surface water (like a stream or river) or groundwater. Most auto recyclers qualify for coverage under the general permit.

Some facilities do not discharge their wastewater directly into a surface water body, but discharge into a sanitary sewer system/sewage treatment plant. If your wastewater is not discharged into a surface water body like a stream or river, but rather to a sanitary sewer system/sewer treatment plant, you will likely need a permit. See the Department's Wastewater Discharge Permit Application for more information. As an automotive recycler, you may qualify to obtain coverage under the state's Minimal Discharge Industrial Wastewater Application.

Pretreatment. To meet the standards of your local sewer authority, you may need to install treatment equipment such as an oil/water separator to prevent oil and sludge from being discharged to the sewer. This is referred to as "pretreatment." In some cases, the skimmed oil can be managed with your used oil. See the ECAR Used Oil Fact Sheet. However, sludge collected by pretreatment equipment will have to be periodically removed and disposed of, possibly as a hazardous waste (you must make a hazardous waste determination). In most instances, wastewater will require some form of pretreatment prior to discharge into the sewer system.

Spills. When a chemical spill or release occurs in Colorado, there are a number of reporting and notification requirements that must be followed by the agency or individual responsible for the spill. These requirements tend to be confusing, and regulations often overlap.

At minimum, notify the Colorado 24-hour Emergency Spill/Release Reporting Line at 877-518-5608 and the Local Emergency Planning Committee at 303-273-1622, immediately or within 24-hours. Refer to the Spill Response Fact Sheet to determine your reporting requirements.

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

CDPHE Discharge Requirements

Wastewater Discharge Permit Application

Minimal Discharge Industrial Wastewater Application

Federal Safe Drinking Water Act Requirements

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 process wastewater? Are the discharges authorized by a 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 or written authorization for all industrial water discharges.
  2. Has the water been pretreated? Depending on which POTW you discharge to, you may be required to obtain a pretreatment permit from the POTW. Check to make sure you have the appropriate permits.
  3. 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.

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, consider having 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 more information, contact the Colorado Department of Health and Environment's Pretreatment Program at 303-692-3618 or the Permits Unit at 303-692-3500.
  2. To report a spill or leak, at minimum, call the Colorado 24-hour Emergency Spill/Release Reporting Line at 877-518-5608 and the Local Emergency Planning Committee at 303-273-1622, immediately or within 24-hours. Refer to the Spill Response Fact Sheet to determine your reporting requirements.
  3. To report an environmental incident or complaint, contact the nearest regional office.

Related ECAR Fact Sheets

  1. Stormwater

Other Relevant Resources

  1. Colorado - List of Pretreatment Coordinators by POTW
  2. Colorado's Automotive Salvage Yard Waste Management Practices



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