How Do Cruise Ships Get Fresh Water?

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Have you ever stopped to wonder where cruise ships get all their fresh water? Think about it – the biggest ships have 6,000 passengers as well as a large crew that all need to average around a half gallon of drinking water a day, plus then there’s all the water used for cooking, showering and so on…

cruise ship tap water

Even if you weren’t thinking about it, you are now! So, let’s take a look at where ships get all their fresh water.

Where do cruise ships get their drinking water?

Cruise ships make their own drinking water. It’s unsurprising since they’re constantly surrounded by sea water – they use either steam evaporation or reverse osmosis processes to desalinate the water before minerals and chlorine are added.

It’s the same as a home filtration system, only significantly larger.

Cruise ships do have large stores for bringing water onto the ship at port, but there’s still nowhere near enough space to store all the drinking water needed for a cruise. Not if you also want to eat, anyway. And since it’s easier to create drinking water than it is to source food in the middle of the ocean, food storage is prioritised.

The minerals added to the desalinated water are for flavour, while chlorine is a cleaning agent which will kill any unwanted bacteria. Don’t worry, it won’t taste like pool water, it’s a much lower amount – the same that would be in typical tap water.

water machine on a cruise ship
Water dispenser on P&O Cruises’ Iona

The water from dispensers generally tastes better than the tap water in your cabin. That’s because it’s filtered a second time and cooled to a more pleasant temperature for drinking.

How many gallons of fresh water does a cruise ship hold?

Cruise ships tend to be able to store around 500,000 gallons of fresh water in massive tanks in the hold. Once it’s been used by passengers for laundry, showering or in the toilet, it’ll be treated before it’s released into the ocean.

Ships make take fresh water on board at ports, but this isn’t suitable for drinking, and instead is limited for use in laundry, cooling the engines or as ballast. The drinking water tends to only be taken from the seawater that undergoes desalination.

River cruise ships tend to have much smaller water stores, and so need to top up their fresh water supplies at each port. This is less of an issue since they don’t usually go for days in between each port.

How clean is cruise ship water?

Cruise ship water is generally very clean. It goes through intensive filtration processes to make sure it is safe to use. And there are rules about water recycling – water that has been used won’t be re-used for passengers on the ship.

Instead, used water is separated into grey water (laundry and showers) and black water (toilet) before being treated appropriately.

It then gets released into the oceans after it has been rendered safe, which must be done at a safe distance from land as dictated by the International Maritime Organization.

Is cruise ship water drinkable?

Unless you are told otherwise, cruise ship tap water is safe for drinking. It is heavily filtered and chlorinated to an appropriate level to remove any toxins, with minerals added to make it taste a lot more pleasant too.

Some ship engineers have even supposedly described the drinking water on cruise ships as being healthier than bottled water. While that’s anecdotal, you shouldn’t be concerned about drinking the tap water unless you’ve been told that there’s a temporary problem.

This is good since bottled water tends to cost extra on a cruise, unless you have a drink package.

cans of water on a cruise
Canned or bottles water is available for an extra charge

You should avoid drinking the water in the shower though – that’s good life advice, not just on a cruise ship.

A couple of other points worth mentioning – firstly, the ice on board is made using the same drinking water that’s been through the same processes. It’s handled carefully to the same standards as any food on board.

So, even if you don’t intend to drink the tap water, you can at least know that the ice cubes in your drink are also not going to cause you any harm. This is much better than many holiday resorts on land which use tap water to make ice, even when the tap water isn’t safe to drink.

Secondly, while the water on a cruise ship is safe for drinking, it might have a slightly different level of chlorine than tap water and so might not be suitable for baby formula. Also if you need distilled water for a medical reason, you should avoid tap water.

Suggested read: How to Feed Your Baby on a Cruise

Speak to your cruise line – they’ll have different policies on how much water you can bring on board if you have a specific need, and while they can always provide bottled water and usually they can source distilled water for you, it may be a paid-for extra. Some luxury ships may have it available for you free of charge.

What are cruise ships swimming pools filled with?

Many cruise ship pools are filled with treated seawater. Chemicals are used to make sure it is clean and safe to swim in. Some ships will use fresh water and others will offer both – so you can see just how much more buoyant you are in a saltwater pool.

The trend seems to be that more modern cruise ships lean towards freshwater pools, which is probably a sign that the freshwater is easier to maintain and keep filtered.

The salt content of seawater will damage pumps over time, after all. And the modern larger ships have more storage space so they can filter in more fresh water than older ships would be able to.

cruise ship pools
Fresh water swimming pool on Anthem of the Seas

How do cruise ships get hot water?

Cruise ships will have a robust hot water system on board to deliver the hot water around the ship where it is needed. Despite being a temporary home to thousands of passengers at once, it’s rare to see complaints about cold or low pressured showers.

The fresh water that’s been desalinated will be fed into different plumbing systems throughout the ship for drinking, cooking and for showers and baths. It’s heated through the consumption of whatever fuel is used on the ship, before being pumped around each deck as required.

It’s not really any different to a typical domestic hot water system at home – just significantly larger and with a lot more plumbing involved.

cruise ship bathroom
You can drink the tap water in your room but it may not be very cold

To conclude

It would be strange for a cruise ship to be surrounded by so much water and not try to take advantage, so you probably expected that ships used some sort of purification process to make sea water safe for drinking and washing. And now you know you were right.

You can wash in fresh clean water, your food will be prepared in safe water too, and you can feel comfortable drinking the tap water – if you aren’t too busy enjoying the soft drinks, cocktails and Champagnes, anyway.

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2 thoughts on “How Do Cruise Ships Get Fresh Water?”

  1. If I go through a cruise expert/agency, will they advise on documents/visas necessary for the trip, as it is a bit of a mind field and I want to ensure that everything is correct.

    • Hey Stephen, yes any good travel agent will tell you everything you need to know about any travel documents you need. Ask them when you book and they should explain what you need and where to get it from, if it’s not something they can sort for you.

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