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Please note: This summary is provided to help you understand the regulations. Consult the references provided for links to the full text of the regulations.

Clean Water Act (CWA)

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The Clean Water Act (CWA), is the cornerstone of surface water quality protection in the United States. The CWA does not deal directly with groundwater nor with water shortage issues. Under authority of the CWA, EPA and state environmental agencies employ a variety of regulatory and non-regulatory tools to reduce direct and indirect pollutant discharges into waterways, finance municipal wastewater treatment facilities, and manage polluted runoff. These tools are employed to achieve the broader goal of restoring and maintaining the chemical, physical, and biological integrity of the nation's waters so that they can support "the protection and propagation of fish, shellfish, and wildlife and recreation in and on the water."

Aspects of the Clean Water Act that are most likely to affect transportation facilities are covered in this section. These include:

Industrial Wastewater

Industrial wastewaters may be generated at transportation facilities during maintenance and cleaning operations. The Clean Water Act made it unlawful to discharge any pollutant from a point source (discrete conveyances such as pipes or man-made ditches) into navigable waters, unless a permit was obtained. Permits for discharges are acquired through EPA's National Pollutant Discharge Elimination System (NPDES) permit program. NPDES permits are obtained by businesses if they discharge directly to a stream or other water course. If a business discharges their wastewater to a municipal sewer system (also called Publically Owned Treatment Works or POTW) it is the responsibility of the municipality to obtain the NPDES permit. In turn, the municipality requires businesses to obtain local connection and discharge permits. Businesses that use a septic system are regulated by local ordinances and are prohibited from discharging certain types of wastes into those units.

Discharges from lavatories are also regulated under the CWA through state rules and local ordinances similarly to residential discharges and are not discussed in this section.

Transportation facility industrial wastewater may contain a variety of pollutants that are regulated by the CWA:

  • "Priority pollutants" including various toxic metals (e.g., lead, chromium)
  • "Conventional pollutants," such as biochemical oxygen demand (BOD), total suspended solids (TSS), fecal coliform, oil and grease, and low or high pH
  • "Non-conventional pollutants," any pollutant not identified as either conventional or priority.

Direct discharges - Transportation facilities that discharge wastewater straight to surface waters (or through any conveyance system through which water flows and then discharges directly to surface waters,) are direct dischargers.

Direct dischargers must obtain a permit under EPA's National Pollutant Discharge Elimination System (NPDES) program. A NPDES permit sets limits, often referred to as effluent limits, on the amount of pollutants that can be discharged to surface waters. For certain categories of facilities, national minimum limits have been established by EPA, which are referred to as effluent guidelines (these are discussed later in this section).

Discharges from Vessels - Under the Clean Water Act, EPA regulates discharges from vessels that are operating in U.S. waters, including:

  • discharges incidental to the normal operation of vessels, including, among others, bilgewater, ballast water, deck runoff/washdown, and grey water, and
  • sewage discharges.

Discharges incidental to the normal operation of vessels are regulated under the NPDES program discussed above. For discharges from vessels, EPA has issued the Vessel General Permit (VGP). This permit applies to all non-recreational, non-military vessels of 79 feet or greater in length which discharge in waters of the U.S., including the 3 mile territorial sea and all navigable waters of the Great Lakes. In addition, the ballast water discharge provisions also apply to any non-recreational vessel of less than 79 feet or commercial fishing vessel of any size discharging ballast water. Recreational vessels as defined in the Clean Water Act are not subject to this permit. In addition, with the exception of ballast water discharges, non-recreational vessels less than 79 feet (24.08 meters) in length, and all commercial fishing vessels, regardless of length, are not subject to this permit. For more information, see Vessel General Permit.

Vessel sewage is generally controlled by regulating the equipment that treats or holds the sewage and through the establishment of areas in which the discharge of sewage from vessels is not allowed:

  • Section 312 of the CWA requires the use of operable, U.S. Coast Guard-certified marine sanitation devices (MSDs) onboard most vessels.
  • The Act also provides for the establishment of no discharge zones (NDZs), specific areas in which the discharge of sewage from vessels is not allowed. Within NDZ boundaries, vessel operators are required to retain their sewage discharges (treated and untreated) onboard for disposal at sea (beyond three miles from shore) or onshore at a pump-out facility.

For more information, see Vessel Sewage Discharge. Also, please note: The EPA issued the 2013 VGP on April 12, 2013, with an effective period of December 19, 2013, to December 18, 2018 (i.e., five years). On December 4, 2018, the President signed into law the Vessel Incidental Discharge Act (VIDA). VIDA requires EPA to develop new national standards of performance for commercial vessel incidental discharges and the U.S. Coast Guard (USCG) to develop corresponding implementing regulations. The VIDA legislation also extended the 2013 VGP's provisions, leaving them in effect until new regulations are final and enforceable.

The NPDES Permit:

  • Specifies the amount of pollutants (e.g., effluent limits) that can be discharged based on categorical effluent standards that are based on available wastewater treatment technology or on the specific treatment technology or on specific water quality standards of the surface water.
  • Generally requires a facility to routinely conduct monitoring and submit reports (requirements are determined on a facility specific basis).
  • Requires that all records related to monitoring be maintained by the facility for at least three years.
  • May contain other site specific requirements, such as construction schedules, best management practices, additional monitoring for non-regulated pollutants, and spill prevention plans.

Indirect discharges - Transportation facilities that discharge wastewater into a sewer system that leads to a municipal treatment plant, also known as Publicly Owned Treatment Works (POTW) are indirect dischargers. The POTW typically is owned by the local municipality or a regional board or sewer authority.

In response to potential problems caused by industrial wastewater being discharged into POTWs, federal pretreatment regulations were developed. These regulations apply to all industrial facilities, including transportation facilities. Local POTWs with approved pretreatment programs have responsibility for enforcing pretreatment requirements. The POTWs have permit criteria similar to NPDES permits (I.e., maximum pH, TSS, BOD, etc.,) but they are set and enforced by the POTW.

Effluent Guidelines - Effluent Guidelines are national standards for wastewater discharges to surface waters (direct discharges) and publicly owned treatment works (POTWs) (indirect discharges). EPA issues effluent guidelines for categories of industrial sources. The standards are technology-based, I.e. they are based on the performance of treatment and control technologies (e.g., Best Available Technology). Effluent guidelines are not based on risk or impacts of pollutants upon receiving waters. Effluent Guidelines that potentially impact transportation facilities include:

Businesses that fall into one or more of these categories must meet the effluent guideline discharge standards and comply with specified monitoring, reporting and recordkeeping requirements.


Transportation facilities must either obtain permit coverage or submit a no exposure certification form for stormwater associated with their operations. If new construction is planned, a separate stormwater permit is needed.

Industrial Activities

Activities, such as fueling, material handling and storage, equipment maintenance and cleaning, or other operations that occur at industrial facilities are often exposed to stormwater. The runoff from these areas may discharge pollutants directly into nearby waterbodies or indirectly via storm sewer systems, thereby degrading water quality.

In 1990, the U.S. Environmental Protection Agency (EPA) developed permitting regulations under the National Pollutant Discharge Elimination System (NPDES) to control stormwater discharges associated with eleven categories of industrial activity, including transportation facilities. As a result, NPDES permitting authorities, which may be either EPA or a state environmental agency, issue stormwater permits to control runoff from these industrial facilities.

The industrial stormwater program requires permit coverage for a number of specified types of industrial activities, including vehicle maintenance, equipment cleaning, or airport deicing operations. However, when a facility is able to prevent the exposure of ALL relevant activities and materials to precipitation, it may be eligible to claim no exposure and qualify for a waiver from permit coverage.

If you are regulated under the industrial permitting program, you must either obtain permit coverage or submit a no exposure certification form, if available.

Throughout most of the nation, EPA has delegated the stormwater program to the states to administer as they see fit, so long as minimum federal requirements are met. Therefore, in most states you will submit your no exposure certification or permit application to your state environmental agency.

However, some states may not yet have the authority to administer this program. For the following states, you need to submit your certification or permit application to your Regional EPA office: Alaska, Idaho, Massachusetts, New Hampshire Texas, Florida, Maine, and Arizona. If your facility is in one of these states, we suggest contacting both your Regional EPA office and state agency to find out where to submit your paperwork.


Stormwater runoff from construction activities can have a significant impact on water quality. As stormwater flows over a construction site, it can pick up pollutants like sediment, debris, and chemicals and transport these to a nearby storm sewer system or directly to a river, lake, or coastal water. Polluted stormwater runoff can harm or kill fish and other wildlife.

The NPDES stormwater program requires construction site operators engaged in clearing, grading, and excavating activities that disturb one acre or more to obtain coverage under an NPDES permit for their stormwater discharges. Although these are federal rules, they are implemented by state environmental agencies (except for Massachusetts, New Mexico, Alaska, Idaho and New Hampshire where EPA retains authority). To obtain forms and more information on application procedures and permit requirements for construction projects in your state, use the CICA Stormwater: Overview.

Spill Prevention, Control and Countermeasure (SPCC) rule

The Spill Prevention, Control and Countermeasure (SPCC) rule (40 CFR 112), promulgated under the Clean Water Act, is a regulation that applies to facilities that store, use and consume oil and oil products. In the transportation sector, the rule applies to many terminals and maintenance facilities, depending on their location and the amount of oil stored on site.

Facilities that meet the criteria (have sufficient storage capacity, and could reasonably discharge to navigable waters or adjoining shorelines) must comply with the SPCC regulations. These regulations require the facility owner/operator to prepare and implement an SPCC plan for their facility. This plan must be well thought out and prepared in accordance with good engineering practices. It must document the location of storage vessels, types of containment, dangers associated with a major release of material from the tanks, types of emergency equipment available at each site, and procedures for notifying the appropriate regulatory and emergency agencies .