Water Filtration Machine (Subnautica)

The Water Filtration Machine is an Interior Piece that makes water and salt. It is made with the Habitat Builder inside either a Multipurpose Room or Large Room.
Overview
| Property | Details |
|---|---|
| Category | Seabases / Interior Pieces |
| Description | Turns seawater into water and salt. |
| Hull Integrity | -1.7 Units |
| Acquired From | Fragments |
| Perks | Produces Salt and Large Filtered Water |
| Debug Spawn | basefiltrationmachine |
Acquisition
The blueprint for the Water Filtration Machine is acquired by scanning Fragments. These fragments can be found in the following locations:
- Wrecks
- Bulb Zone
- Dunes
- Degasi Seabases (Story Spoiler)
- Jellyshroom Cave

Use
A Water Filtration Machine uses Energy from a Seabase to desalinate seawater, making Salt and Large Filtered Water (+50 water).
- It takes about 15 minutes and 40 seconds to produce one Large Filtered Water.
- It produces 1 unit of water every 18.8 seconds.
- It takes 7 minutes and 40 seconds to produce one Salt.
As the player loses 1 unit of water every 20 seconds, one Water Filtration Machine is more than adequate to care for the player's water needs.
Power Consumption
A single Water Filtration Machine uses 0.85 points of Energy per second, or 51 Energy per minute. It can be powered nonstop with four Solar Panels above 100m depth or almost nonstop with one Bioreactor.
If powering a Water Filtration Machine with a fuel-using energy source, particularly if using a Bioreactor, each Large Filtered Water takes 799 energy to produce. If the machine has been emptied, this means that a reserve of at least 1,598 energy will be needed to avoid the base running out of power.
Construction and Placement
Building a Water Filtration Machine has a base Hull Integrity penalty of 1.0 units and takes up one wall. It will not block the construction of other base components that take up a wall (Windows, Reinforcements, Wall Planters, etc.) on the two wall panels to either side.
- Eight can be built per Multipurpose Room.
- Water Filtration Machines can share a Multipurpose Room with a Nuclear Reactor or Bioreactor but not with an Alien Containment.
Inventory and Operation
The four Storage slots of a Water Filtration Machine are sectioned into two slots for salt and two for water. If one resource is taken from the machine it will continue operating but generate only that resource: it is not necessary to remove the salt for it to make more water or vice versa. It will cease operation and not draw power once its inventory is filled.
Above Water Operation
A Water Filtration Machine can be built above water but will produce no salt, and only make water at 1/8th of the speed below water. Perhaps this is because it can also draw and condense moisture from an atmosphere, though the Databank entry only says the water comes "from an external source."
Salt Applications
While the Water Filtration Machine's primary purpose is producing Large Filtered Water, it is also an infinite source of Salt Deposits, which can be used for purposes that work well with the production of water.
- Additional water source: Salt can be used with Coral Tube Samples to produce Bleach, which in turn is used to produce 2 bottles of Disinfected Water, each giving an additional 30 units of water. Thus, a Machine with a full inventory will provide up to 220 units of water. You can take advantage of this by building your base near Giant Coral Tubes, which are pretty much infinite as well.
- Curing food: Salt can be used to cure edible fauna, which will make them a bit dehydrating but prevent them from decomposing, thus making them suitable for long outings without a source of sustenance. You can use an Alien Containment to breed Reginalds, which are the most nutritious edible fauna. When combined together with a Large Filtered Water it will provide 48 units of water and 44 units of food. A Machine with a full inventory will provide double that, i.e., 96 units of water and 88 units of food, which is around 7 times that of a single Marblemelon which uses the same amount of inventory space and would eventually decompose.
Recipe
The Water Filtration Machine is constructed using the Habitat Builder.
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Requires:
- 2x Titanium
- 2x Copper Wire
- 1x Aerogel
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Produces:
- 1x Water Filtration Machine
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Data Bank Entry
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The filtration system draws water unfit for human consumption from an external source, atomically splits it into its constituent parts, and outputs consumable liquid water and salts, while disposing of any harmful by-product. It can be built in any compatible habitat module, but has substantial power requirements.
'The Alterra Water Filtration System: Any liquid into pure, refreshing, pH-balanced water? Yes sir, ANY liquid!'
Gallery
Front
Side
Side
Water Filtration Machine producing a Large Filtered Water
Water Filtration Machine exterior seawater intake panel
Water Filtration Machine model from Sketchfab
Highpoly model from Sketchfab
Trivia
- When the Water Filtration Machine was originally added it was extremely cheap to build, requiring only 2 Titanium and nothing else.