Oxygen Not Included Wiki

Spaced Out Banner.png has fresh updates every other day!

Please excuse our tardiness while we try to keep the Wiki up to date!

If you want to help out, head on over to the Discord Logo.pngDiscord Server in the #wiki-collab channel to learn how.


Oxygen Not Included Wiki
This article has not been revised for the current version (U40-494396). It was last updated for LU-356355. It may contain inaccuracies.
This article has not been revised for the current version (U40-494396). It was last updated for LU-356355. It may contain inaccuracies.

Lavatory is a building used by Duplicants to empty their bladders. It requires Water intake and produces Polluted Water and Food Poisoning Germs. Some of these germs are left on each Duplicant that uses it. It is an upgrade from the Outhouse, as it uses plumbing to dispose of waste and produces fewer Germs.


The Lavatory is a hygienic way to provide a place for Duplicants to relieve themselves, and thus reduce Stress and the spread of Diseases.

It also fulfills the 'Toilet' criteria for the Latrine in the Room Overlay, which provides a +1 morale bonus to Stress reduction. Furthermore, it fulfills the 'Flush Toilet' criteria for the Washroom in the Room Overlay, which provides +2 morale bonus.

It also fulfills the 'Toilet' criteria for the Hospital room.

The Lavatory outputs more fluid than it takes in, so it can be used to recover minuscule amount of Water or Dirt when paired with a Water Sieve. Each duplicant with normal bladder will produce at least ~11.16 g/s Water, which, for example, can recoup a ninth of their daily oxygen demands down the line. However, the amount of excess water added is small enough that to keep an Electrolyzer running non-stop, it would require 90 Duplicants to use the bathroom each cycle.

If adding the water produced to your supply, you would have to worry about disinfecting the Polluted Water, which will have millions of germs in them.


The Lavatory uses 5 kg of Water and produces 11.7 kg of Polluted Water, both of which are carried through pipes. The resulting Polluted Water is the combination of the 5kg of input Water temperature and 6.7kg of 37°C newly created Polluted Water, which means the Lavatory will equalize a Bathroom Loop temperature to 37°C over time.

One use of the Lavatory produces 105,000 Food Poisoning germs. These germs are divided among the Duplicant, the Polluted Water, and the Lavatory itself as follows:

  • Duplicant: +3,350 germs
  • Polluted Water: +100,000 germs
  • Lavatory: +1,650 germs


  • Water Sieves do not remove germs from polluted water. Therefore, it isn’t recommended to refine the Polluted Water from your lavatories and then mix it with your main water supply without processing it through something like a chlorine room or other germ-killing processes, as this will get many of your duplicants sick.
  • The Lavatory is a recommended upgrade from the Outhouse, as it is more hygienic and efficient, and does not require Duplicant maintenance.
  • Having an equal number (or greater) of hand-washing stations as toilets and pointing the arrows in the exit direction will ensure all dupes wash their hands, with too few wash stations some dupes may skip washing if multiple are leaving at the exact same time.
  • If the fluid exit pipe is shared with a common header, the lavatory will become unusable whenever fluid passes through the pipe. To prevent this use at least a 1 pipe long header piece before joining with a main pipeline.
  • It can be used to cool water above 37°C or heat water below 37°C by using its heat equalization effect.