Wastewater and Storm Water Management Information

Shop Tour Stop #2
The following questions and guidance are taken from the Consolidated Screening Checklist for Automotive Repair Facilities Guidebook.

A √ next to a response in the guide indicates that is the preferred response in terms of environmental compliance. If you select a response without a √, you may still be in compliance; however, you should verify that you are in compliance by contacting the appropriate federal or state regulatory agency and discussing your activity with them.


Automotive facilities may discharge wastewater and/or storm water from the following activities: repair and maintenance of on-site vehicles, vehicle and equipment cleaning, building and grounds maintenance, chemical storage and handling, fueling of vehicles, and painting and paint removal operations. Facilities that discharge wastewater are required to have a National Pollutant Discharge Elimination System (NPDES) permit and/or state permit if the wastewater is collected and discharged off-site through a distinct pipe or ditch to the waters of the United States.  See Glossary of Terms for the complete definition of waters of the United States.  EPA or an authorized state issues NPDES permits. For more information regarding commercial activities, review this EPA site: http://cfpub1.epa.gov/npdes/home.cfm?program_id=14Persons responsible for wastewater discharges requiring an NPDES permit must apply for an individual permit or seek coverage under a general permit (if available) at least 180 days before discharge of wastewater begins. Some states do not allow certain discharges into the environment.

Discharges to Publicly Owned Treatment Works (POTW)

Publicly-owned treatment works are treatment plants that receive and treat wastewater through municipal sanitary sewers prior to discharge to waters of the United States. They may also be referred to as municipal wastewater treatment plants. POTWs may implement a pretreatment program and regulate discharges to the sanitary sewer through prohibitions on certain discharges or limit the amount of the discharge. Automotive shop owners or managers should contact their local POTW to see if any pretreatment requirements or limits apply to them. Although contacting the POTW is not a federal requirement, the facility could be liable if it discharges a significant amount of oil, or other automotive fluids, and those discharges cause the POTW to violate its own NPDES permit.

Can the facility identify the final destination of its wastewaters?

Do you know the destination of your shop’s wastewaters? Does the interior or exterior drain discharge to:

Yes–Facility can identify the final destination of all wastewaters (e.g., POTW, underground injection well, waters of the United States).  √

No–Facility cannot identify the final destination of its wastewaters.

N/A–Facility does not have drains.

How does the facility manage its wastewater?

There are several methods a facility can use to manage its wastewater. The treatment method most likely to be used at an automotive repair shop prior to discharge wastewater is an oil-water separator. This treatment removes oily fluids and grit before the wastewater discharges directly to waters of the United States, or to a sanitary sewer leading to the POTW. Wastewater treatment may be required by an NPDES permit or by the POTW.

Waters of the United States–Facility discharges effluent directly to waters of the United States, in accordance with NPDES storm water permit.  √

Sanitary sewer–Facility discharges to a municipal sanitary sewer or combined sewer with permission of the POTW.  √

UIC well–Facility discharges to a UIC well, generally via a floor drain. Although there are some exceptions, as a general rule, discharging industrial wastewater to a UIC well is NOT appropriate.

Ground–Facility discharges onto the ground. Wastewater may affect groundwater or may flow into storm sewers and surface waterways. Caution: Many states forbid the disposal of washwater/rinsewater onto the ground.

Other–Method of disposal is not listed.

N/A–Facility does not discharge wastewater.

If the facility discharges to waters of the United States, does it have an NPDES permit?

A facility needs an NPDES permit to discharge industrial wastewater directly into waters of the United States. The wastewater may need treatment on-site to reduce pollutant concentrations to meet the NPDES permit limits. Some states give one NPDES permit which includes both wastewater and storm water discharge requirements while other states give separate permits.

Yes–Facility has an NPDES permit.  √

No–Facility does not have an NPDES permit.

N/A–Facility does not discharge wastewater directly to a body of water.

If discharging to a municipal sanitary sewer, has the facility notified the POTW and received approval for discharges?Facilities should contact the POTW if any pretreatment requirements apply to them. Although contacting the POTW is not a federal requirement, the facility could be liable if it discharges a significant amount of oil or other material, and that discharge causes the POTW to violate its own NPDES permit.

Yes–Facility has contacted POTW and has received approval for discharges.  √

No–Facility has not contacted POTW and has received approval for discharges.

N/A–Facility does not discharge to a POTW.If discharging to a underground injection control (UIC) well, does the facility comply with UIC program requirements?Note: The use of Class V UIC wells for motor vehicle waste disposal, or the disposal of any other hazardous waste, is prohibited. For more information, call the Safe Drinking Water hotline at (800) 426-4791.

Automotive shops that discharge industrial wastewater to underground injection control (UIC) wells must comply with the rules established under the UIC program. Class V wells include shallow non-hazardous industrial waste injection wells, septic systems, and storm water drainage wells. At automotive facilities, the most common injection wells are used drain clarifier, washrack and storm water to soil below the site, especially in areas where sewer connection is unavailable. Metals, solvents, fuels, and other automotive fluids disposed through these injection wells are likely to violate UIC regulations. Employing dry clean-up methods, waste segregation, and other best management practices may minimize UIC liability. The best protection against UIC liability is to convert to zero-discharge systems for all shop areas, and ensuring no storm water makes contact with motor vehicle fluids.

Class V UIC wells are authorized by rule provided they do not endanger underground sources of drinking water and meet certain minimum requirements. UIC requirements stipulate that facilities must submit basic inventory information about a Class V well to the EPA or the primacy state agency. In addition, many UIC primacy state programs have additional prohibitions or permitting requirements. However, the fluids released by certain types of Class V wells, particularly motor vehicle and industrial wells, have a high potential to contain elevated concentrations of contaminants that may endanger drinking water, and if found on your property, may be subject to characterization (lab analysis, ground water monitoring) and closure requirements. For more information, review the publication How The New Motor Vehicle Waste Disposal Well Rule Affects Your Business. It can be found at: www.epa.gov/safewater/uic/smallcompliance.pdf

Yes–Facility complies with UIC program requirements.  √

No–Facility does not comply with UIC program requirements.

N/A–Facility does not discharge industrial wastewater to UIC wells.

How does the facility manage the sludge from an oil/water separator?Oil/water separators, which are typically connected to floor drains or wash racks, remove grit and oily materials from wastewater. Oil-water separators require periodic servicing to maintain their performance. Prior to cleaning an oil/water separator, test the contents of the grit chamber and the oily sludge for hazardous constituents. If the sludge exhibits any characteristic of a hazardous waste, the facility must handle it as a hazardous waste. If the sludge is nonhazardous, manage it as used oil.

Managed as hazardous waste–Facility disposes hazardous sludge off-site. It is stored, manifested, transported, and disposed of in compliance with all provisions of the hazardous waste program.  √

Off-site disposal to other facility–Facility disposes nonhazardous sludge off-site. It is transported, and disposed of at an approved treatment or disposal facility.  √

Landfill–Facility improperly landfills its oil/water separator sludge.

N/A–No sludge is produced.

Storm Water Discharges

Under the Clean Water Act, it is illegal to discharge any pollutants into waters of the United States from a point source unless the discharge is authorized by a National Pollutants Discharge Elimination System (NPDES) permit. The storm water regulations identify eleven major categories that are associated with industrial activity. Facilities that fall under these eleven industrial categories must apply for a NPDES storm water discharge permit. While automotive service and repair shops did not fall into any of the eleven industrial categories, an automotive shop may still need a storm water permit because the shop is located in an ‘urbanized area.’ Urbanized area is defined as having one or more places (central place(s)) and the adjacent densely settled surrounding area (urban fringe) that together have a residential population of at least 50,000 and an overall population density of at least 1,000 people per square mile. Contact your state or EPA regional office for more information regarding an NPDES permit for storm water discharge. Additional information on the storm water program can be found at: http://cfpub1.epa.gov/npdes/home.cfm?program_id=6

How does the facility manage its storm water?

Storm water (rain, snow) and other forms of water (e.g., washing overspray) are a potential source of wastewater at a facility. Storm water discharges begin when rain or overspray comes in contact with materials left unprotected outdoors. These materials can range from spills left uncleaned, storage containers, or vehicle or mechanical parts. To prevent contact with storm water, store materials on pallets (or something else that keeps them off the ground) and cover them with a tarp or under a roof. Close dumpsters and seal them to the extent that storm water will not enter or exit the dumpster. The pollutants in storm water depend on the type of material(s) the rain comes in contact with prior to discharge. A facility may ‘treat’ storm water using an oil-water separator or some other method of treatment to reduce pollutant concentrations prior to discharge either to waters of the United States, or to a sanitary sewer or combined sewer leading to a POTW. An NPDES permit or the POTW may require wastewater treatment.

Waters of the United States–Storm water discharges go directly to waters of the United States, in accordance with NPDES storm water permit.  √

Sanitary sewer–Storm water discharges are directed to a municipal sanitary sewer or combined sewer with permission of the POTW.  √

UIC well–Storm water discharges go to a UIC well (via a floor drain). Although there are some exceptions, as a general rule, discharging industrial wastewater to a UIC well is NOT appropriate.

Other–Method of storm water management is not listed.

N/A–Facility does not discharge wastewater.

Does the facility have a storm water pollution prevention plan (SWPPP)?If a facility must obtain an NPDES storm water permit, it will likely be required to prepare and implement a storm water pollution prevention plan (SWPPP). Automotive repair shops must develop SWPPPs to prevent storm water from coming in contact with potential contaminants.

Yes–Facility has an SWPPP.  √

No–Facility does not have an SWPPP.

N/A–Facility is not required to have an SWPPP.Is a certification included in the storm water pollution prevention plan?Each SWPPP must include a certification, signed by an authorized individual, stating that discharges from the site have been tested or evaluated for the presence of nonstorm water discharges. The certification must include the following:

If certification is not feasible, the storm water pollution prevention plan must describe why (e.g., no access to discharge sites).

Yes–Facility’s SWPPP includes a certification.  √

No–Facility’s SWPPP does not include a certification, or certification is not feasible and facility has included an explanation in the SWPPP.

N/A–Facility is not required to have an SWPPP.

Are materials stored outside protected from contact with storm water?

Yes–Facility protects materials from rain/snow or overspray.  √

No–Facility does not protect materials from rain/snow or overspray.

N/A–Facility does not store materials outside.How does the facility clean the floors and surrounding areas?

Dry Cleanup–Facility uses ‘dry methods’ such as dry mop, broom, rags, absorbents, etc., thus reducing generation of contaminated wastewater.   √  √Note: See list below.

Water–Facility uses a hose or wet mop, thus generating wastewater.Suggested Dry Cleanup Methods


Source: U.S. EPA Office of Enforcement and Compliance Assurance, EPA 305-B-03-004, October 2003.

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