33 CFR 151.1504: Definitions for ballast water management rules

Last reviewed: October 14, 2026

This section defines terms used in this subpart on ballast water management. It covers equipment terms, geographic terms such as the Great Lakes and the EEZ, and terms such as voyage and constructed.

Applies toThe definitions apply as the terms are used in this subpart.

What it says

  1. An alternate management system (AMS) is a ballast water management system approved by a foreign administration under the standards of the International BWM Convention. It must also meet all applicable requirements of U.S. law, and it is used in lieu of ballast water exchange.

    “and meeting all applicable requirements of U.S. law, and which is used in lieu of ballast water exchange”
  2. Ballast water means any water and suspended matter taken on board a vessel to control or maintain trim, draught, stability, or stresses of the vessel, regardless of how it is carried.

    “means any water and suspended matter taken on board a vessel to control or maintain, trim, draught, stability, or stresses of the vessel, regardless of how it is carried”
  3. A ballast water management system (BWMS) includes all ballast water treatment equipment and all associated control and monitoring equipment.

    “The BWMS includes all ballast water treatment equipment and all associated control and monitoring equipment.”
  4. A vessel is constructed at a stage of construction when its keel is laid.

    33 CFR 151.1504(1)“The keel of a vessel is laid;”
  5. A vessel is also constructed when assembly has commenced and comprises at least 50 tons or 1 percent of the estimated mass of all structural material, whichever is less.

    33 CFR 151.1504(3)“Assembly of the vessel has commenced and comprises at least 50 tons or 1 percent of the estimated mass of all structural material, whichever is less; or”
  6. A vessel is also constructed when it undergoes a major conversion.

    33 CFR 151.1504(4)“The vessel undergoes a major conversion.”
  7. A voyage is any transit by a vessel destined for the Great Lakes or the Hudson River, north of the George Washington Bridge, from a port or place outside of the EEZ. It includes intermediate stops at a port or place within the EEZ.

    “from a port or place outside of the EEZ, including intermediate stops at a port or place within the EEZ”

Common questions

What counts as ballast water?

Ballast water is any water and suspended matter taken on board a vessel to control or maintain trim, draught, stability, or stresses of the vessel. It does not matter how the water is carried.

“means any water and suspended matter taken on board a vessel to control or maintain, trim, draught, stability, or stresses of the vessel, regardless of how it is carried”

What is a ballast tank?

A ballast tank is any tank or hold on a vessel used for carrying ballast water. It counts even if the tank or hold was not designed for that purpose.

“means any tank or hold on a vessel used for carrying ballast water, whether or not the tank or hold was designed for that purpose”

How far does the Exclusive Economic Zone extend?

The EEZ extends seaward 200 miles from the base line of the territorial sea of the United States. It also includes the equivalent zone of Canada.

“which extends from the base line of the territorial sea of the United States seaward 200 miles, and the equivalent zone of Canada”

What does port mean in this subpart?

A port is a terminal or group of terminals, or any place or facility, that the COTP has designated as a port.

“means a terminal or group of terminals or any place or facility that has been designated as a port by the COTP”

The text of 33 CFR 151.1504

Electronic Code of Federal Regulations (eCFR), current as of April 16, 2026 · Read it on eCFR

Definitions

The following terms are defined as used in this subpart.

Alternate management system (AMS) means a ballast water management system approved by a foreign administration pursuant to the standards set forth in the International Maritime Organization's International BWM Convention, and meeting all applicable requirements of U.S. law, and which is used in lieu of ballast water exchange.

Ballast tank means any tank or hold on a vessel used for carrying ballast water, whether or not the tank or hold was designed for that purpose.

Ballast water means any water and suspended matter taken on board a vessel to control or maintain, trim, draught, stability, or stresses of the vessel, regardless of how it is carried.

Ballast water management system (BWMS) means any system which processes ballast water to kill, render harmless, or remove organisms. The BWMS includes all ballast water treatment equipment and all associated control and monitoring equipment.

Captain of the Port (COTP) means the Coast Guard officer designated as COTP of either the Buffalo, NY, Marine Inspection Zone and Captain of the Port Zone or the New York, NY, Captain of the Port Zone described in part 3 of this chapter or an official designated by the COTP.

Commandant means the Commandant of the Coast Guard or an authorized representative.

Constructed in respect to a vessel means a stage of construction when—

(1) The keel of a vessel is laid;

(2) Construction identifiable with the specific vessel begins;

(3) Assembly of the vessel has commenced and comprises at least 50 tons or 1 percent of the estimated mass of all structural material, whichever is less; or

(4) The vessel undergoes a major conversion.

Exclusive Economic Zone (EEZ) means the area established by Presidential Proclamation Number 5030, dated March 10, 1983, (48 FR 10605, 3 CFR, 1983 Comp., p. 22), which extends from the base line of the territorial sea of the United States seaward 200 miles, and the equivalent zone of Canada.

Environmentally sound method means methods, efforts, actions, or programs, either to prevent introductions or to control infestations of aquatic nuisance species, that minimize adverse impacts to the structure and function of an ecosystem, minimize adverse effects on non-target organisms and ecosystems, and that emphasize integrated pest management techniques and non-chemical measures.

Great Lakes means Lake Ontario, Lake Erie, Lake Huron (including Lake Saint Clair), Lake Michigan, Lake Superior, and the connecting channels (Saint Mary's River, Saint Clair River, Detroit River, Niagara River, and Saint Lawrence River to the Canadian border), and includes all other bodies of water within the drainage basin of such lakes and connecting channels.

Port means a terminal or group of terminals or any place or facility that has been designated as a port by the COTP.

Sediments means any matter settled out of ballast water within a vessel.

Voyage means any transit by a vessel destined for the Great Lakes or the Hudson River, north of the George Washington Bridge, from a port or place outside of the EEZ, including intermediate stops at a port or place within the EEZ.

Waters of the United States means waters subject to the jurisdiction of the United States as defined in 33 CFR 2.38, including the navigable waters of the United States. For 33 CFR part 151, subparts C and D, the navigable waters include the territorial sea as extended to 12 nautical miles from the baseline, pursuant to Presidential Proclamation No. 5928 of December 27, 1988.

Sections it refers to

The plain-English explanation on this page was written with AI from the regulation text above and checked automatically before publishing: every quote appears in the text, every number comes from it, and a second model confirmed each statement adds nothing the text doesn't say. Regulation text current as of April 16, 2026. The regulation text governs. RegKnot is not affiliated with the U.S. Coast Guard.