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MassDEP Wastewater Regulations: What You Need to Know
Holding Tanks
If your shop temporarily discharges IWW to a holding tank before it is hauled offsite for treatment or discharge, you must submit a one-time compliance certification to MassDEP (310 CMR 18.00) unless your IWW holding tank was previously approved by the agency. You must file online here.
If your shop discharges IWW to a sewer, you must meet local sewer discharge requirements. Contact your local sewer authority to make sure you are in compliance.
Discharging to the Sewer
If your shop discharges greater than 25,000 gallons per day to a sewer authority that does not have an approved Industrial Pretreatment Program (under regulatory amendments 314 CMR 7.00 promulgated in April 2014), you must obtain a sewer connection permit from MassDEP. This is a very large volume of wastewater that may only affect larger shops or those with car washes. MassDEP Sewer Connection Forms can be found here.
Best Practices
Prevent Shop Waste Water From Entering the Environment
Shops must have floor drains or a network of water collection troughs to ensure that any IWW generated within the shop is collected and does not flow outside the shop and into the environment. Shop owners should confirm that any water used to clean spray booths, washing floors, vehicles, and various other activities are collected and do not leave your property.
Install an Oil-Water Separator
If you do not have a wastewater storage tank, the use of an oil-water separator is required. An oil-water separator removes oily fluids and sludge from wastewater before it is discharged into a sewer connection. It is important to service your oil-water separator to maintain its performance. The bottom sludge will eventually have to be collected and handled according to waste management requirements—you should determine if the sludge should be classified as hazardous waste or waste oil.
Ensure Floor Drains Do Not Discharge Into the Ground
All floor drains must only discharge to municipal sewers or approved industrial wastewater holding tanks. Floor drains may never discharge into the ground.
Clean Spills Appropriately Before Washing Your Floor
When a shop rinses or washes their floor, oil, grease, paint chips, and other debris enters your wastewater stream. Clean spills (see the fact sheet on “Spill Prevention and Cleanup”) prior to ever rinsing down your floors. This can help ensure you are not liable for any violations and are in compliance with your local sewer authority. In addition, shops must make sure that chemical storage areas (e.g., paint mixing rooms, hazardous waste storage areas, etc.) are designed to contain unexpected leaks to prevent chemicals from entering your wastewater or the environment.
Find Additional Information
- Section 2 of this EPA checklist highlights important practices for managing wastewater at auto repair shops. See: Consolidated Screening Checklist for Automotive Repair Facilities Guidebook.
- King County, Washington, has a fact sheet on selecting and maintaining oil-water separators. See: Fact Sheet: The Oil/ Water Separator, How to select and maintain an oil/water separator.
- EPA created a fact sheet on oil-water separators (OWS), including basic procedures for handling vehicle and floor wash water, and techniques to improve OWS performance and reduce costs and liabilities. See: Oil/Water Separators 1999.
- For more information on holding tank regulations, see this page: Regulation of Industrial Wastewater Holding Tanks and Containers.
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