Vessel Sewage Discharges: Statutes, Regulations, and Related Laws and Treaties

You will need Adobe Reader to view some of the files on this page. See EPA’s About PDF page to learn more.While the U.S. Environmental Protection Agency (EPA) generally regulates vessel sewage discharges into the U.S. navigable waters through implementation of Clean Water Act (CWA) section 312 and its associated regulations, sewage discharges from certain vessels may also be subject to regulation under other federal statutes or international treaties.


Clean Water Act Section 312 (33 U.S.C. 1322)

CWA sections 312(a) – (m) provide the statutory framework under which the EPA and the U.S. Coast Guard regulate sewage discharges from vessels. See Clean Water Act Section 312 (33 U.S.C. 1322 (PDF)(10 pp, 170 K)). 

Note on the relationship between CWA sections 312 and 402:
Section 301(a) of the CWA provides that "the discharge of any pollutant by any person shall be unlawful" unless the discharge is in compliance with certain other sections of the Act. 33 U.S.C. 1311(a). The CWA defines "discharge of a pollutant" as "(A) any addition of any pollutant to navigable waters from any point source, (B) any addition of any pollutant to the waters of the contiguous zone or the ocean from any point source other than a vessel or other floating craft." 33 U.S.C. 1362(12). A "point source" is a "discernible, confined and discrete conveyance" and includes a "vessel or other floating craft." 33 U.S.C. 1362(14). A person may discharge a pollutant without violating the section 301 prohibition by obtaining a National Pollutant Discharge Elimination System (NPDES) permit under section 402 of the CWA. (33 U.S.C. 1342 (PDF)(8 pp, 164 K)).

Vessel sewage discharges defined in CWA section 312 are excluded from Vessel General Permit (VGP) coverage although certain vessels are required to obtain coverage under EPA's NPDES VGP for discharges incidental to the normal operation of those vessels (see below for information on the VGP). While sewage is defined as a "pollutant" under the CWA, sewage from vessels within the meaning of section 312, is exempt from this statutory definition [33 U.S.C. 1362(6); see also 33 U.S.C. 1322(a)(6) (definition of "sewage")]. Sewage from vessels also includes graywater for commercial vessels operating on the Great Lakes and is also exempt [33 U.S.C. 1322(a)(10) (definition of "commercial vessels" for purposes of section 312)]. Therefore, vessel owners/operators are not required to obtain NPDES permits before discharging sewage. However, vessels discharging graywater and sewage in one effluent stream, and are not otherwise "commercial vessels" under CWA section 312, are required to follow the requirements outlined in CWA section 312 and the VGP.

Implementing Regulations

The EPA regulations implementing CWA section 312 (standards for marine sanitation devices (MSDs)): 40 C.F.R. 140 et seq (PDF)(5 pp, 229 K).

U.S. Coast Guard regulations implementing CWA section 312 (regulations governing the design, construction, certification, installation and operation of MSDs): 33 C.F.R. 159, Subparts A-D (PDF)(18 pp, 273 K).

Related Laws and Treaties

Sewage discharges from certain vessels may also be subject to regulation under other Federal statutes and/or international requirements. Examples of these regulations include Title XIV, which applies to certain cruise ships operating in Alaska, and MARPOL Annex IV, which applies if the vessel's flag State is a party to Annex IV. Discharges of graywater and sewage that have been mixed into one effluent stream are also regulated under the NPDES VGP, issued by the EPA pursuant to section 402 of the CWA.

"Title XIV" (33 U.S.C. 1901 Note)

On December 21, 2000, Congress enacted an omnibus appropriation bill that included new statutory requirements for certain cruise ships discharging graywater and sewage in Alaska [Departments of Labor, Health and Human Services, and Education, and Related Agencies Appropriations Act, 2001, Pub. L. No. 106-554, 114 Stat. 2763, enacting into law Title XIV of Division B of H.R. 5666, 114 Stat. 2763A-315, and codified at 33 U.S.C. 1901 (PDF)(7 pp, 154 K) Note ("Title XIV")].

Title XIV did not supersede regulation of sewage discharges from cruise ships under CWA section 312. Rather, Title XIV establishes separate requirements for the discharge of treated sewage and graywater from those cruise ships with capacity for 500 or more passengers and operating in certain waters in Alaska. Like the CWA section 312 program, Title XIV is jointly implemented by the EPA and the U.S. Coast Guard.

Vessel Discharge Permit Program (Vessel General Permit)

Pursuant to section 402 of the CWA, 33 U.S.C. 1342 (PDF)(8 pp, 164 K), the VGP, finalized by the EPA in 2008, regulates discharges incidental to the normal operation of vessels operating in a capacity as a means of transportation. Recreational vessels as defined in section 502(25) of the CWA are not subject to the VGP. 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 the VGP.

The VGP includes:

  • general effluent limits applicable to all covered discharges;
  • general effluent limits applicable to 26 specific discharge streams; 
  • narrative water-quality based effluent limits;
  • inspection, monitoring, recordkeeping, and reporting requirements; and
  • additional requirements applicable to certain vessel types.

Vessel sewage discharges within the meaning of CWA section 312 are excluded from coverage under the VGP. However, as noted above, graywater and sewage discharges mixed into one effluent stream are subject to the permit (except those discharges from "commercial vessels" (as defined at 33 U.S.C. 1322(a)(10)) operating on the Great Lakes). This one effluent stream must meet the discharge limitation requirements in Parts 2 and 5 (if applicable) of the VGP, and any applicable CWA section 312 requirements for sewage discharges.

See Vessel Discharge Permit Program (Vessel General Permit).


The principal international instrument regulating sewage discharges from vessels is Annex IV to the "International Convention for the Prevention of Pollution from Ships, 1973, as modified by the Protocol of 1978 relating thereto" ("MARPOL Annex IV"). The United States is not a party to MARPOL Annex IV, and thus is not bound by the Annex's provisions. However, ocean-going vessels operating in U.S. navigable waters which are registered in foreign countries may be subject to the MAPROL Annex IV requirements.

More information regarding MARPOL Annex IV can be accessed on the IMO websiteExit