How Do Cruise Ships Get Fresh Water?

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Most mega-ships contain 6,000 guests and a sizable onboard crew. If everyone consumes an average of half a gallon of drinking water daily, a large volume of freshwater is consumed.

Furthermore, this guesstimation doesn’t include water used for showering, cooking, brushing teeth, etc. This leads people to wonder how cruise ships get fresh water when they’re surrounded by salt water.

How Do Cruise Ships Get Fresh Water?

It is not surprising to most people to note that cruise ships make their own drinking water. Ships are out at sea, so it makes sense that they would do this when you consider what seawater is composed of. 

Most cruise lines use either reverse osmosis processes or steam evaporation to desalinate water (remove the salt content) before adding chlorine and minerals to make it safe for consumption. This method is the same for home filtration systems, only on a larger scale.

Each ship contains large stores used for bringing some water onto each vessel while at port. However, there isn’t enough space available onboard to hold all the water necessary for a cruise.

Water for Guests at Cruise Ship Gangway
Water for Guests at Cruise Ship Gangway (Photo Credit: Camera walk / Shutterstock)

It is easier for each vessel to generate potable water at sea rather than sourcing food. When you are floating in the middle of an ocean, the top priority is food storage.

The added minerals are for flavor. Chlorine is only used as a cleaning agent to eliminate unwanted bacteria, but it will not affect the taste. The drinking water won’t taste like you are drinking water from a pool since the amount used is much lower. The amount used is the same amount that is contained in tap water.

Cruise Line Innovation for Sourcing Fresh Water

Royal Caribbean has initiated a Save the Waves program aboard their ships. They have taken the initiative to produce the majority of the clean water they use, producing over 90% of what is consumed by private destinations and operating each vessel.

Sourcing Fresh Water

This works by using a few methods for purifying the water. These include:

  1. Aeration. Aeration involves forcing air through a sink faucet and showerhead. It provides enough water pressure in each bathroom. Air is used for pressure compared to forcing the water out of a showerhead at a high volume. Guests can comfortably shower, and the cruise ship saves water. 
  2. Steam Evaporation. Also called steam desalination or flash evaporation, steam evaporation uses heat and steam from a ship’s engine to boil seawater. As water evaporates, the salt remains as a by-product. Freshwater condenses back into distilled purified water.
  3. Reverse Osmosis. Reverse osmosis is the second way cruise ships convert seawater into drinking water. Reverse osmosis utilizes low-energy methods in pushing saltwater through a microscopic membrane. The membranes are so tiny that only clean water will get through. The intake side blocks contaminants and salt, allowing water to pass through. It is then mineralized to add flavor.
  4. Bunkering. This method involves finding fresh water that is locally sourced when at port and storing it on the ship. After collecting it, the crew tests it for any pollutants and treats it to ensure no unwanted components. Ships never use bunkers in places containing water shortages.
  5. Condensing Water. Clean water is conserved or made while on board. Condensation is the most effective way of saving water. Water from air conditioners is reused for laundry and is free since it was previously generated.

The Best Place for Tasty Water on a Ship

If you obtain your water using a dispenser, it tastes better than the tap water found in cabins because it has been filtered a second time. After the second filtration, the water is cooled to a pleasant temperature and used for drinking.

The Amount of Fresh Water Cruise Ships Can Hold

Most ships can store 500,000 gallons of fresh water in massive tanks located in the hold area. After guests have used the water for showering, toilet water, laundry, etc., the crew treats it before releasing it into the ocean. 

A cruise ship will bring fresh water onboard when they visit ports. However, this water is not for drinking. This water is used for laundry, as ballast, or to cool the engines. Water used for drinking is usually taken from seawater undergoing a desalination process.

Water Pump in Port
Photo Credit: zlikovec / Shutterstock

River cruise ships have smaller water stores. Fresh water supplies are topped up during each port visit, which isn’t a huge problem since their travels don’t run several days between port visits.

How Clean Is the Water on a Cruise Ship?

The water consumed aboard cruise ships is extremely clean. Using an intensive filtration process, each cruise ship ensures that the water is safe for guests. There are also rules regarding recycling water. The vessel will not reuse water for other guests aboard the ship.

The water used becomes separated into grey water used for showers and laundry. It is also separated from black water used for the toilet before being treated and released into the ocean.

Cruise Ship Hot Tub Water
Photo Credit: Sucharn Wetthayasapha / Shutterstock

According to the International Maritime Organization, cruise ships must process all water safely away from nearby land.

Is Cruise Ship Water Drinkable?

Unless otherwise indicated, tap water from a cruise ship is safe to drink. All water is chlorinated at appropriate levels and heavily filtered to remove remaining toxins. Minerals are added for a more pleasant taste.

Many ship engineers comment that cruise ship drinking water is healthier than bottled water. While it appears somewhat anecdotal, it is safe to drink tap water unless you hear of any issues, which is a good thing. Bottled water costs extra when you are on a cruise unless you purchase drink packages.

The only water that you should not consume is that found in the shower. This water is grey water and has been used before. The filtration process is not as thorough as for tap water; thus, you can get sick from drinking it.

All ice on board uses the same process as for making drinking water. The ice is handled with the same care as the food standards. Therefore, even if you choose not to drink tap water, the ice cubes found in your drink will not harm you, either. 

This process is safer than ice cubes found in some holiday resorts located on land. These resorts sometimes use tap water when making ice, despite it being unsafe.

Read Also: Can I Take a Wine Opener on a Cruise?

Additionally, while cruise ship water is safe for consumption, there may be a bit of a different chlorine level compared to ordinary tap water. Therefore, it may not be safe to use it to make baby formula. If you require distilled water for medical reasons, you should also avoid using tap water found on your cruise.

You can discuss it with your cruise line if you need to bring water on board for medical reasons. Most have different policies on the amount of water brought on board. They can also provide bottled water for you and source distilled water if you require it. You may need to pay for this service, but some luxury lines may provide it at no extra cost.

How Do Ships Get Hot Water?

Most cruise ships contain a robust system for delivering hot water where it is needed. Even though ships become temporary homes filled with thousands of people simultaneously, complaints about cold or low-pressure water are rare.

Desalinated fresh water goes into a different pumping system in the ship. It is used for cooking, baths, showers, and drinking. The heating process involves fuel consumption before pumping it around each deck.

The process is no different than a domestic hot water process. It is only done on a much larger scale in addition to more pumping. 

What Water Is in Cruise Ship Pools?

Interestingly, pool water is just treated seawater. Chemicals are added to ensure the ocean water is sanitary and safe for swimming. Some cruises will use fresh water, and others will use both. Most modern cruises use freshwater pools, which may indicate that it is easier to filter and maintain.

Best Cruise Lines for Adults
Photo Credit: Vintagepix / Shutterstock

The salt in seawater damages pumps after enough time has elapsed. Modern ships contain more storage, so they can filter in additional freshwater better than older ships. 


How do cruise ships get fresh water? They use many different methods to purify the water through various processes and reuse as much water as possible for other components on the ship. This is a clever way of reducing consumption and keeping everything safe for the environment.

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