Waste Management

Advice on waste management when boating.

UK legislation around waste management has generally been transposed from International Directives established by the international maritime community at the International Maritime Organization (IMO). In this part of the website you can find information on and links to relevant sites regarding sewage and waste management whilst boating.


With more and more of us taking to the water each year it is important we all know how to deal with our waste in a responsible manner. It is no longer acceptable to pump waste out whenever and wherever it suits and it is our responsibility to consider the effects this may have on the surrounding environment.

There are three terms which are commonly used to distinguish the different types of waste water created on boats: black water, grey water and bilge water.

  • Black water is toilet waste and this raw sewage often contains harmful bacteria and viruses.
  • Grey water is waste water from on board sinks, showers and washing machines.
  • Bilge water is self explanatory but is often contaminated with oil and fuel, and can be a pathway for invasive, non-native species.

Black water discharges are likely to become less common over time as, since 2006, the Recreational Craft Directive (RCD) has required all new vessels to have provision for a holding tank to be fitted. In the majority of cases, grey water discharges directly into the water.

Levels of sewage input from recreational craft are thought to be relatively small compared to direct inputs from sewage treatment works but the effects are serious and can potentially affect water quality in a number of ways. Raw sewage poses a serious health risk to humans, adversely affects shellfish and reduces oxygen levels in the water, while grey water discharge leads to nutrient enrichment and algal blooms. As a result, it is our responsibility as recreational boaters to be aware of the rules regulating the disposal of garbage and sewage.

Regulations and Best Practice

Regulations for the prevention of pollution by sewage are contained in Annex IV of MARPOL. These regulations apply to ships of 400 gross tonnage and above engaged in international voyages or ships which are certified to carry more than 15 persons.

Although no specific provisions are made for smaller pleasure vessels, it is important to consider the impact of discharging raw sewage from a sea toilet or holding tank into the sea. It is best practice to return all waste generated on board to shore waste reception facilities where possible.

If a holding tank is fitted it should be used and only emptied at either a pump out station or when more than 3 miles offshore. This is because in the open sea waste will be quickly diluted and dispersed by wave action and currents. On vessels without a holding tank avoid the use of toilets in poor tidal flushing areas (e.g. estuaries, inland waterways, inlets and crowded anchorages) and use marina or shore facilities where possible.

There are many other countries where the direct overboard discharge of sewage is prohibited by the authorities. The provision of holding tanks of sufficient capacity to store waste for discharge to shore facilities may be needed for a vessel to comply with legislation in these countries.

To find out more visit The Green Blue website where there are practical tips and advice you can follow to reduce your impact on the environment whilst boating.

Further information is available on the International Maritime Organization (IMO) and the Maritime and Coastguard Agency (MCA) websites.

Pump-out directory

In order to assist and encourage recreational boaters in locating and using pump-out facilities within the UK, The Green Blue has produced a series of maps covering both inland and coastal areas. These are divided into regions and give both the location and contact details for each provider. Regional maps and further advice and information on this issue can be found on The Green Blue Marine Environmental Facilities Map, which includes details of places offering pump-out, grey water disposal, and other facilities.

The Canal and River Trust maintain a list of their own water points and pump outs, as well as a private pump out directory.


Whilst onboard it is easy to accumulate a fair amount of refuse and unlike at home where you have your wheelie bin just outside there is very little space to store it. Sadly, the quantity of litter found in our ocean, seas and along our coasts is rising and this has a serious impact on the environment and wildlife. Marine litter does not provide a suitable habitat or artificial reef for marine organisms, and most litter is not easily broken down and absorbed by the sea. Plastic litter can persist in the marine environment indefinitely. A small fraction of the estimated 4 – 13 million tonnes of annual marine litter comes from recreational boating, but every sector has a responsibility to follow best practice.

Refuse means all food, domestic and operational wastes produced on board (except sewage). This includes food wastes, paper products, rags, glass, metal, bottles, crockery and similar refuse from all vessels.

The basic principles are:

- put no refuse into the sea

- retain refuse on board and dispose of it ashore, recycling where possible. 

Following MARPOL Annex V, the UK has strict rules on dumping refuse at sea with substantial penalties for offenders. Food wastes may only be disposed of at sea if they have been pulverised and you are at least 3 miles offshore (12 miles in the North Sea or English Channel). There are rules for ports and terminal operators to provide adequate disposal facilities ashore.

To find out more visit The Green Blue website. Further information is available on the International Maritime Organization  (IMO) and the Maritime and Coastguard Agency (MCA) websites.