The National Pollutant Discharge Elimination System (NPDES) is a program created by the EPA (authorized under the Clean Water Act) to protect U.S. waters from pollution. Specifically, the Clean Water Act forbids anyone from discharging any pollutant from a point source into navigable waters, unless a permit was obtained. Point source pollution is defined as any single identifiable source of pollution from which pollutants are discharged, such as pipes, ditches, smokestacks, tunnels, containers, and storm drains. Concentrated Animal Feeding Operations (CAFOs) also fall under this definition, as animal waste can enter water bodies as raw sewage.
In essence, this program serves to protect our waters—groundwater, surface waters, and drinking water—by regulating the maximum quantity of pollutants and total daily maximum loads (TMDLs), as well as the type of pollutant (chemicals, sediment, oil, etc.). NPDES permits are administered by state agencies or EPA regional offices, and these regulatory bodies have permission to conduct inspections at facilities they may be violating the Clean Water Act.
NPDES requirements are specific to sites with primary activities and/or SIC codes (NAICS can be converted to SIC codes_ under any of the eleven categories of industrial activity (pictured below) that is discharging into receiving waters. For example, a site involved with metal processing can have SIC codes of 3452 (bolts, nuts, screws, rivets, and washers) and 3471 (electroplating, plating, polishing, anodizing, and coloring). Due to these operations, they must monitor their discharges and ensure no pollutants are being deposited into nearby bodies of water or groundwater.
There is a notable exception to needing an NPDES permit: if a facility is sending their discharge into a municipal sanitary sewer system or a combined sewer system, you may not require an NPDES permit, but you still need to consult the municipality and NPDES permitting authority to document that you are complying with the laws and to verify that the effluent can be treated properly.
There are three different types of NPDES permits: no exposure, general, and individual permits. Regardless of general or individual permits, all facilities must conduct routine inspections, monitor their discharge, retrieve and analyze water samples, have a Storm Water Pollution Prevention Plan (SWPPP) and review it every year, implement methods and BMPs to prevent pollution, issue annual training, and report spills if any occur. Other facilities, after stopping industrial activity, must adhere to all the terms listed in a no exposure permit, including verifying that no industrial elements or activities are exposed to the weather, and that there are no illicit connections or unauthorized discharges to the storm water system.
Permits are valid for up to five years, though renewals must be submitted at least 180 days before expiration to ensure the renewal can be adequately reviewed by the regulatory agency. In Michigan, every facility that has the authorization to discharge industrial stormwater on January 1st is required to pay an annual permit fee. Depending on your location, there may be additional fees associated with permit applications, Notices of Intent, and/or permit coverage.
When it comes to NPDES permits, a good rule of thumb is: “would I drink this water?” If it looks and/or smells unclean, it probably is. To prevent pollution on your site, keep industrial equipment and activities indoors as much as possible, and protect your storm drains. Sweep often and perform other housekeeping duties on a regular schedule. Lastly, keep your spill kits stocked and train a team on how to react in case a spill occurs. When in doubt, don’t be afraid to reach out: you can contact the EPA, local agencies, and of course, Clean Stormwater!
