Water & Hydration

Even though you’re surrounded by water, you need to have a source of drinkable water. You’ll find bottles of water in places throughout the game, but it’s imperative to learn how to provide hydration on your own. Fortunately, there are several options to acquire water in Subnautica to keep you hydrated!

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Bladderfish (+20 hydration)

Bladderfish are the purple, rounded heart-shaped fish found in the Safe Shallows area where you first start the game (by your lifepod). They can be caught by swimming up to them and grabbing them with your hands and using a deployable grav trap can make that even easier.

Eating a bladderfish raw will add +6 to your food needs, but -4 for water. However, the fabricator will convert bladderfish into a 6oz bottle of filtered water that’s +20 for hydration. This is one of the easiest ways to stay hydrated when starting the game.

Recipe

• 1 bladderfish

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Disinfected Water (+30 hydration)

Another way to acquire water using the fabricator is by making bleach. Bleach is made from salt and coral tube sample. Salt can be found in chunks on the ocean floor all over the map. To get coral tube samples, simply use your knife to hit one of the large coral tubes (big tan tubes found in the safe shallows). Combine 1 salt with 1 coral tube sample in the fabricator to make bleach. Then use the bleach in the fabricator to make a 12oz bottle of disinfected water, which has a +30 hydration.

Recipe

• Bleach
  • 1 salt
  • 1 coral tube sample
• Disinfected water
  • 1 bleach

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Water Filtration Machine (+50 hydration)

The water filtration machine is a great way to automate water production by turning sea water into water and salt (if in a building underwater; building it above water/on land will only generate water). Note that it only has 4 total slots for the salt and water so you will need to frequently empty it to keep a continuous flow of fresh water.

The water filtration machine will likely generate more salt than you’ll need for crafting, but it can be used to cure fish for food. A great way to have a steady stream of food and water is to build an alien containment, stock it with Peepers and they’ll reproduce over time. Cured peeper has +32 food and -2 H2O, but if you’re generating bottles of water using the water filtration machine, each will provide +50 H2O to counter the small dehydration from the cured fish.

Finding the Water Filtration Machine
One of the easiest places to find the water filtration machine is in the mushroom caves, located S/SE from your starting lifepod (Aurora to your left – the lifepod ladder faces SW, so you’ll want to stay to the left of it). Once you get to the mushroom cave entrance, the location is approximately 265m down, so be mindful if your Seamoth cannot handle that – you’ll need to exit it at a safe depth and swim the rest of the distance down.

Building the Water Filtration Machine

• 3 titanium
• 1 copper wire (made of 2 copper ore)
• 1 aerogel (made of 1 gel sack + 1 ruby)

This video shows where both gel sacks and rubies can be found:

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Coffee Vending Machine

There’s also a coffee vending machine you can craft to provide some semblance of a normal life while trapped on this ocean planet. It generates coffee without needing any resources, so it can be helpful in a pinch if you need quick hydration. It produces 2 “coffee americanos” into your inventory, each providing +4 H2O.

Recipe:

• 2 titanium

Finding the Coffee Vending Machine

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Hydrating Foods

In addition to water, you can get hydration from foods so it’s helpful to grow these foods in a garden. They’re also helpful for powering the bioreactor. I keep at least one garden by my bioreactors for this purpose.

• Bulbo Tree: +8 food, +10 H2O
• Chinese Potato: +12 food, +3 H2O
• Marblemelon: +12 food, +14 H2O