05/13/2026
The main international legal instrument for ballast water is the International Convention for the Control and Management of Ships’ Ballast Water and Sediments, 2004, commonly called the Ballast Water Management Convention or BWM Convention. It was adopted by IMO to prevent the transfer of harmful aquatic organisms and pathogens through ships’ ballast water and sediments.
Ballast water is operationally necessary: ships take it on board to control trim, list, draught, stability, and structural stresses. However, when ballast water is taken up in one region and discharged in another, it can transfer non-native species, bacteria, viruses, plankton, larvae, and other organisms. These may become invasive, damage ecosystems, affect fisheries, harm coastal infrastructure, and create public-health risks. The Convention therefore requires ships to manage ballast water according to approved procedures, technical standards, and certification requirements.
Why Ballast Water Management Matters
A ship may load ballast water in one port, cross an ocean, and discharge that water in another coastal environment. The organisms inside the ballast tanks may survive the voyage and establish themselves in the receiving ecosystem. This is why ballast water is considered one of the major pathways for the spread of invasive aquatic species.
For maritime cadets and ship officers, ballast water management is not just an environmental topic. It is connected to:
ship stability and safe loading condition;
port State control inspections;
record keeping;
operation of ballast water management systems;
survey and certification;
sediment management;
legal compliance under IMO rules;
and increasingly, digital record-keeping and system-performance verification.
Core Structure of the BWM Convention
The Convention establishes requirements for ships to manage ballast water and sediments through several key elements:
Ballast Water Management Plan
Each applicable ship must carry and implement an approved Ballast Water Management Plan. The plan explains how ballast water operations are conducted safely and in compliance with the Convention.
Ballast Water Record Book
Ships must record ballast water operations, including uptake, discharge, exchange, treatment, internal circulation, use of reception facilities, accidental discharges, system failures, sediment handling, and general remarks. The 2023 and 2024 amendments have made this area especially important.
International Ballast Water Management Certificate
Applicable ships must be surveyed and certified. The certificate confirms the ship’s ballast water management method and compliance status.
Ballast Water Performance Standards
The two most important standards are D-1 and D-2.
D-1 and D-2 Standards
The D-1 standard refers to ballast water exchange. Under this older method, ships exchange ballast water at sea to reduce the risk that coastal organisms from one region will be discharged into another port environment.
The D-2 standard is the modern biological performance standard. It requires ships to meet limits on viable organisms in discharged ballast water. In practice, this normally requires a type-approved Ballast Water Management System, often using filtration, ultraviolet treatment, electrochlorination, chemical treatment, deoxygenation, or combinations of technologies.
The major regulatory direction is clear: the Convention has moved from transitional reliance on D-1 exchange toward mandatory D-2 treatment.
Implementation Schedule: Regulation B-3
One of the important earlier amendments in the attached documents is Resolution MEPC.297(72), adopted on 13 April 2018, which amended Regulation B-3 on the implementation schedule for ballast water management. This amendment entered into force on 13 October 2019.
The revised Regulation B-3 sets out when different ships must comply with the D-2 standard. In simple terms, ships constructed on or after 8 September 2017 must meet the D-2 standard from delivery. Ships constructed before that date were given a phased implementation schedule linked mainly to the relevant renewal survey. For ships where the renewal-survey trigger did not apply, the Administration had to set a compliance date, but not later than 8 September 2024.
This means that the global transition period has effectively reached its final stage: by September 2024, ships subject to the Convention were generally expected to comply with the D-2 biological standard unless an exemption, exception, alternative method, or special arrangement applies.
Survey and Certification Requirements
The Convention includes detailed survey and certification requirements under Section E. Ships must undergo initial, renewal, intermediate, annual, and additional surveys as applicable. These surveys verify that the ship’s Ballast Water Management Plan, equipment, systems, fittings, arrangements, and materials comply with the Convention.
Resolution MEPC.299(72), adopted on 13 April 2018, amended Regulations E-1 and E-5 concerning endorsement of additional surveys on the International Ballast Water Management Certificate. These amendments entered into force on 13 October 2019. The changes clarified survey endorsement arrangements, including references to annual or intermediate surveys.
For ship operators, this means that compliance is not only about installing equipment. The ship must maintain valid certification, keep the system operational, follow the approved plan, and record ballast water operations properly.
Commissioning Testing of Ballast Water Management Systems
A major practical update came through Resolution MEPC.325(75), adopted on 20 November 2020, which amended Regulation E-1 and Appendix I of the BWM Convention. These amendments entered into force on 1 June 2022.
The key change is that an initial survey must confirm that a commissioning test has been conducted for any installed ballast water management system. The purpose of commissioning testing is to validate the installation and demonstrate that the system’s mechanical, physical, chemical, and biological processes are working properly.
This is very important because a ballast water management system may be type-approved, but poor installation, wrong integration, sensor problems, pipework issues, power-supply problems, filter malfunction, or treatment-dose errors can still lead to non-compliance. Commissioning testing therefore focuses on the actual installed system on board the ship.
The same resolution also amended the certificate form so that the International Ballast Water Management Certificate records the method used, installation date where applicable, manufacturer name where applicable, and whether the ship complies through D-1, D-2, D-4, or another accepted approach.
Ballast Water Record Book: 2025 Update
One of the most important recent updates is Resolution MEPC.369(80), adopted on 7 July 2023, which amended Appendix II of the BWM Convention concerning the Form of Ballast Water Record Book. These amendments entered into force on 1 February 2025. IMO’s January 2025 supplement to the BWM Convention also confirms that MEPC.369(80) entered into force on 1 February 2025.
This update modernizes and expands the record-book format. The revised form requires a diagram identifying the ballast tanks of the ship, corresponding to the approved Ballast Water Management Plan, including multi-use tanks, spaces, or compartments designed to carry ballast water.
The revised Ballast Water Record Book requires entries for several categories of operations:
ballast water uptake from the aquatic environment;
ballast water discharge into the aquatic environment;
ballast water exchange;
internal circulation for treatment or in-tank treatment;
uptake or discharge from or to a port-based or reception facility;
accidental discharge, ingress, or exceptional uptake/discharge;
failures and inoperabilities of the ballast water management system;
ballast tank cleaning, flushing, sediment removal, and sediment disposal;
and additional operational procedures or general remarks.
A particularly important part is the explicit requirement to record failures and inoperabilities of the ballast water management system. The amended form explains that these include malfunctions, shutdowns, or critical alarms that may indicate non-compliance with the D-2 standard, excluding routine information and warnings.
For officers, this is a major operational compliance point. If the system fails, alarms, shutdowns, operational limitations, treatment interruptions, and return to operational status must be properly recorded.
Electronic Ballast Water Record Books: 2025 Update
The most recent amendment in the attached files is Resolution MEPC.383(81), adopted on 22 March 2024, which amends Regulations A-1 and B-2 to allow the use of electronic record books under the BWM Convention. These amendments are scheduled to enter into force on 1 October 2025, after deemed acceptance on 1 April 2025. IMO’s September 2025 supplement also confirms the electronic record book amendments under MEPC.383(81).
The amendment adds a new definition: an electronic record book is a device or system approved by the Administration and used to electronically record entries for each ballast water operation instead of a hard-copy record book.
Regulation B-2 is also amended to state that each ship must have a Ballast Water Record Book, which may be electronic or integrated into another record book or system. Electronic record books must be approved by the Administration, taking into account IMO guidelines.
The amended rule also clarifies signature and verification requirements. Each ballast water operation must be recorded without delay. Each entry must be signed by the officer in charge, and each completed page must be signed by the master. For electronic entries, a group of entries must be verified by the master in a timely manner.
This is a practical digitalization update. It does not reduce the ship’s obligations; it changes the accepted format and approval route for recording them.
IMO Guidance on Electronic Record Books
At MEPC 80, IMO also adopted guidance for the use of electronic record books under the BWM Convention. IMO states that this guidance aims to provide standardized information for approving electronic record books and to support a consistent approach to approval.
This matters because an electronic record book is not simply any spreadsheet or onboard software. It must be approved by the Administration and must preserve the reliability, integrity, traceability, and availability of required ballast water records.
Ongoing Review of the BWM Convention: 2024–2025 Developments
Beyond the formal amendments already adopted, IMO is still reviewing the BWM Convention through the experience-building and convention-review process. IMO states that the list of Convention provisions and associated instruments to be amended, revised, or developed was endorsed at MEPC 81 in March 2024 and updated at MEPC 83 in April 2025, with work still ongoing.
At MEPC 83, held from 7 to 11 April 2025, IMO reported that the review of the BWM Convention was ongoing. Classification and industry summaries of MEPC 83 indicate that the review work is focused on amendments to the Annex of the BWM Convention and the BWMS Code, including continued work by correspondence groups and a target to progress draft amendments for future MEPC consideration.
One important technical discussion at MEPC 83 concerned the performance of ballast water management systems under challenging water quality conditions. DNV’s MEPC 83 summary reports that additional tests on challenging water quality performance during type approval were discussed as mandatory additional evaluations for ballast water management systems.
This reflects a real operational issue: some ballast water management systems perform differently depending on water turbidity, salinity, temperature, suspended solids, organism load, and other local water conditions. The future regulatory trend is therefore moving from basic installation compliance toward stronger evidence of reliable performance in difficult real-world conditions.
Practical Compliance Implications for Ships
For ships and companies, the most important practical requirements are now as follows.
The ship must have an approved Ballast Water Management Plan and must conduct operations according to that plan.
The ship must comply with the relevant D-2 implementation date. For most ships, the transition to D-2 compliance has already reached its final phase, especially after the 8 September 2024 deadline for ships not covered by the normal renewal-survey trigger.
If a ballast water management system is installed, the initial or additional survey must confirm commissioning testing, proving that the installed system is functioning properly.
The Ballast Water Record Book must be maintained carefully. From 1 February 2025, the revised record-book format applies, with more detailed categories for ballast operations, treatment, failures, reception-facility use, sediment handling, and exceptional events.
From 1 October 2025, ships may use an approved electronic Ballast Water Record Book, provided it is approved by the Administration and complies with IMO guidance.
Practical Implications for Cadets and Junior Officers
For cadets, the BWM Convention should be understood as both an environmental regulation and an onboard operational system. The responsible officer must understand when the ship is ballasting, deballasting, exchanging, treating, circulating, or discharging to a reception facility. Each operation must be recorded correctly and without delay.
Cadets should especially remember these operational points:
Ballast water must be managed according to the approved plan.
D-1 means ballast water exchange; D-2 means biological discharge standard, usually requiring treatment.
The ballast water management system must be operated within its approved limits.
Failures, alarms, shutdowns, and inoperability must be recorded.
Sediments are also regulated, not only water.
Incorrect records may create port State control problems even if the equipment is installed.
Electronic records are allowed only when properly approved.
Summary of the Most Recent Regulatory Position
The BWM Convention has moved from a transitional exchange-based regime toward a treatment-based D-2 compliance regime. The major implementation schedule was clarified by MEPC.297(72), with ships constructed on or after 8 September 2017 required to meet D-2 from delivery and older ships phased in mainly through renewal surveys, with a final outside date of 8 September 2024 for ships not covered by the renewal-survey trigger.
The 2022 update through MEPC.325(75) made commissioning testing a key survey requirement for installed ballast water management systems.
The 2025 update through MEPC.369(80) revised the Ballast Water Record Book format and entered into force on 1 February 2025.
The next major update is MEPC.383(81), which introduces electronic Ballast Water Record Books and enters into force on 1 October 2025.
At the same time, IMO’s wider review of the BWM Convention remains ongoing, with current work focusing on future amendments to the Convention Annex, the BWMS Code, and technical issues such as performance testing under challenging water-quality conditions.