Where Does Toilet Waste Go on a Cruise Ship?

By Robert Palmer

When on a cruise ship, it is easy to forget all the details of keeping the experience running smoothly. One of those details is the disposal of toilet waste. This article discusses how a cruise ship deals with these waste products and how it is done safely and sustainably.

Cruise ships are equipped with waste management systems that handle sewage, graywater, and blackwater. Graywater is wastewater from sinks, showers, and laundry machines.

Blackwater is wastewater from toilets. Toilet waste water from the ships’ bathrooms are piped into large tanks known as blackwater holding tanks.

Once a blackwater holding tank reaches capacity, the cruise ship will discharge its contents into the ocean in a process known as ‘black water discharge’. This process requires special treatment before it can be done safely and in compliance with international regulations. The wastewater must be treated to remove any contaminants before it can be discharged into the ocean.

Treatment Process

The wastewater is treated using several methods including chemical treatment, physical filtration, and ultraviolet light exposure. Chemical treatment uses additives such as chlorine to kill any bacteria that may be present in the waste water.

Physical filtration removes larger particles from the water by passing it through filters. Ultraviolet light exposure kills microorganisms like bacteria and viruses.

Once treated, the wastewater can then be safely discharged into the ocean at least three miles away from land or other ships in order to minimize environmental impacts. Cruise ships also use advanced monitoring technologies to ensure that their wastewater discharge meets environmental standards.


Toilet waste on a cruise ship is managed through an advanced wastewater management system which includes chemical treatment, physical filtration, and ultraviolet light exposure to ensure safe disposal of waste into the ocean. The technology also helps ensure that all applicable regulations are met while minimizing environmental impacts.