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This guide starts off where the previous section, The very early game, left off.


I won't go over the stuff from that part here. Instead I'll just pop in a screenshot to show what has been done by the start of this guide.


Starting point. Basic toilets (latrines and wash basins), hamster wheel and oxygen diffuser, both early research stations, a basic farm and a basic bedroom.

  • Some rooms give morale bonuses if they meet certain requirements.

  • You can see the available room bonuses and requirements in the Room Overlay (top right, or press F11).

  • The most important early-game room bonus is the Great Hall (+6 morale).

  • The most common maximum room size is 64 tiles. This equals a 4x16 room: 4 tiles high, 16 tiles wide. (Or 18 tiles wide if you include the outer walls.)

  • The maximum size for a ranch is 96 tiles. This equals a 6x16 room. (6 tiles high, 16 tiles wide - or 18 if you count the outer walls.)

For my fellow neat-freaks

  • If you want a(n unnecessarily) neatly structured base, you can make your floors 18 tiles wide and then vary room height depending on the maximum room size.

  • (But be warned: years ago I read someone suggest it on a forum, and since trying it for the first time I have been both physically and psychologically incapable of ever not building my bases using the X tiles high by 18 tiles wide approach.)

Tip: room sizes - and room bonuses

Room bonuses. Barracks (morale +1), Great Hall (morale +6), Laboratory (+10% research speed), Latrine (morale +1)

A note on the laboratory: Putting the research stations next to the printing pod gives dupes a +15% Lit Workspace buff. This is in addition to the laboratory's +10%, for a nice total of +25% research speed.


Great Hall

Dupes will sit down to eat pretty much anywhere they find a meal, including sitting down in a germy bathroom while themselves still covered in germs from using said bathroom. You can avoid that kind of silliness by giving dupes mess tables to eat at.


Mess Table


Water Cooler


Hanging pot


A Flower Pot with a Bluff Briar plant

  • The mess table is unlocked in Meal Preparation, the second tier of the Food research branch (found at the uppermost edge of the research tree)

Once researched you can find the mess table under Furniture (in the bottom left).

Dupes won't share mess tables, so you will need one mess table per dupe.


If the mess table is in a dining room, dupes will get a morale bonus when eating there. There are two different kinds of dining rooms:

  • Mess Hall (+3 morale)

  • Great Hall (+6 morale)

You can see the room requirements for both rooms in the Room Overlay, the picture of a bed in the top right. A great hall is an easy way to get a significant morale bonus. To qualify as a great hall a room needs:

  • A mess table (for each dupe)

  • A decor item

  • A recreational building

Furthermore, the room cannot have any industrial machinery and must be between 32-120 tiles in size.

The easiest recreational building to get your hands on at the start of the game is the water cooler.

  • The water cooler is unlocked in Employment, the first tier of the Colony Development research branch. (If you have a super computer then you have already unlocked the water cooler.)


Once researched you can find the water cooler under furniture (in the bottom left).


You will also need a decor item (with a value of at least +20 decor). This can be easily taken care of by putting a plant in your dining room.

A plant will require something to plant it in - a Flower Pot, Wall Pot, or Hanging Pot. They are all unlocked in the Decor research branch.

Look around your starting area for a decorative plant. The most common decorative plants in the starting area are Bluff Briar and Mirth Leaf. Either one is fine for this purpose.


Dig up the plant and plant it in the pot. To do that:


  • select the pot, then select the seed to plant in it, then click on Plant.

You can raise the priority of pots to get things planted faster. If nothing happens, you probably forgot to click Plant (I do that a lot).


It's not much, but it's great. Dupes get a +6 morale bonus for eating in a great hall.

  • You can see the Plumbing Overlay by clicking on the water drops in the top right or by pressing F6.

  • You build most plumbing-related stuff through the Plumbing build icon (bottom left). A notable exception is the sink, which is found under Medicine.

  • Plumbing things commonly have an input and an output.

    • White is input: liquid goes in here

    • Green is output: liquid comes out here

  • If something isn't working, the first things to check are the inputs and outputs. A common mistake (even after thousands of hours I still do it) is connecting inputs or outputs wrong.

  • A pipe must lead somewhere for liquid to flow along it. (A Liquid Bridge counts as somewhere - water will flow up to the start of the liquid bridge, even if the pipe goes nowhere after it.)

  • If you want liquid to pour out of a pipe, you need to put a Liquid Vent at the end.

  • Gravity affects liquids on the map, it does not affect liquid in pipes.

Tip: plumbing basics

Toilets and sinks


There are a bunch of useful things that require plumbing. Let's start with upgrading our outhouses and wash basins to toilets and sinks.


Inputs and outputs. When the plumbing overlay is active you will see a reminder of input and output colours. (Yellow is for when you use a liquid filter. We won't need that now.)

Emptying outhouses and wash basins takes time - and produces polluted dirt and germy water. Toilets and sinks require no maintenance, so it's a useful upgrade.

There's a separate part of the guide, Pipes and pumps: liquid and gas flow basics, that goes more in-depth into pumps and pipes and such. But for what we will be building now we'll just need to remember some basics.

  • Plumbing-related buildings can have inputs and outputs. Some have both, some have only one or the other.

  • Inputs are white

  • Outputs are green

Some examples of the stuff you will commonly use:


Toilets and sinks have both an input and an output. Clean water comes into the input to be used by the building. After a dupe has used it, polluted water flows out of the output.

A liquid pump only has an output. It gathers liquid from its surrounding area.

A liquid storage tank, called a liquid reservoir, has an input and an output. The liquid you want to store goes in the input. If you have a pipe connected to the reservoir's output then any liquid in the tank will flow out.

Whenever you connect an input or an output, it is always done using pipes.

Let's start with some pics of what we'll be building. The second picture (below) is of the Plumbing Overlay. You can access the plumbing overlay by clicking on the the drops of liquid in the top right (or press F6).


Plumbing - toilets and sinks. Clean water is pumped to the white inputs. Polluted water will flow out of the green outputs to be stored in a liquid reservoir for later use.






Liquid Pump


Liquid Pipe


Liquid Reservoir

To unlock the things needed for this build, research:

  • Plumbing

  • Sanitation

  • Improved Plumbing

They are all in the Liquids branch of the research tree (which is a bit below the middle of the research tree map).

When you have the necessary buildings unlocked, build something similar to the picture above. (You don't have to hide your pipes in the floor and walls if you don't want to.) (Just know that if you don't, a little piece of me will die.)

I usually leave some empty spaces in my bathrooms for decor items, which is why there are two big empty spots. But decor items aren't necessary; you can instead fit a fourth toilet and sink, or two showers, a compost, etc.

Building your new bathroom includes the following steps (the order you do them in doesn't matter):

  • Build toilets - called Lavatories, found under Plumbing.

  • Build Sinks, found under Medicine.

  • (When deciding where to put toilets and sinks, remember the stuff about germs and making dupes pass a sink to wash their hands after using the bathroom.)

  • Build a Liquid Pump (found under Plumbing) in a body of (clean) water.

  • Build a Liquid Reservoir (found under Home). Placement isn't hugely important, but try to put it somewhere where it won't be in the way for several dozen cycles (or more).

  • Using Liquid Pipe (under Plumbing), connect the water pump to the toilet and sink inputs - the white bits.

  • Also using pipes, connect the toilet and sink outputs (the green bits) to the input (the white bit) of the Liquid Reservoir.

  • The finished piping should go:

    • from the pump to the white bits on the toilets and sinks.

    • from the green bits on the toilets and sinks to the while bit on the liquid reservoir.

  • When finished, connect your Liquid Pump to your power grid (using Wire, under Power).

Water should now start flowing along your pipe(s) and into your toilets and sinks.

Mouseover your toilet. If everything worked it should say "Lavatory Ready." If it doesn't say that (and trust me, we've all been there), it's time to start debugging - start by checking inputs and outputs.

Once everything is up and running you will still need to periodically check your reservoir tank. If it fills up completely, your toilets will stop working and your dupes will have "accidents."


There are two kinds of Oxygen Not Included gamers: those this has happened to, and those this has not yet happened to. Stay in that second group for as long as possible.

If (or when) your liquid reservoir starts filling up, you can simply build a new one next to it and chain them together.


Liquid reservoir chaining options. Liquid flows from left to right. In the top setup liquid will flow to the last tank and start filling the reservoirs from the end. The bottom setup fills tanks from the leftmost tank first.

Tip: leaving doors open

  • It takes a tiny amount of time for dupes to open doors as they pass through them.

  • If there is no reason for a door to be closed, set the door to be left open.

  • Open doors still retain their other settings - who is allowed to pass, what direction dupes are allowed through, etc.

  • If you have Shine Bugs (the bright, flying creatures) in your base, don't leave bedroom doors open. Shine Bugs can fly in and wake up dupes.

  • A Critter standing on the tile of an open door will get a "Confined" debuff (-10 happiness). So I usually don't leave ranch doors open. (Also, critters that can fly or climb walls will quite happily escape through open doors. And then be all like "Oh, was I not supposed to leave? Sorry, I didn't know.")

Polluted water to reed fiber



Thimble Reed


Hydroponic Farm

You now have a steadily increasing supply of polluted water. There are different options for what to do with it. Here we'll cover a simple solution: exchange your polluted water for reed fiber.

(You can also skip this step and go straight to a chlorine-based decontamination build. But if you're a beginner I'd say don't worry about that stuff yet - there's plenty of time to learn how that works later.)

Reed fiber is used for various things, like for making a kind of protective clothing called an atmo suit. You'll be wanting some atmo suits at some point, so having a supply of reed fiber is a good thing.

Reed fiber is harvested from a plant called thimble reed. Thimble reed consumes polluted water to grow, meaning you can feed it all of your polluted water and then get reed fiber in return.

There is a kind of tile called a hydroponic farm tile. It is like a farm tile, but you can connect a liquid pipe to it. This means that you can connect your polluted water pipes straight to a hydroponic farm tile.

Note: when choosing where to build your hydroponic farm tile, keep in mind that thimble reed requires a body temperature of between +22 and +37C to grow.


All hooked up and nothing to grow. The bathroom output is connected to a liquid reservoir, which is connected to a hydroponic farm tile.


Thimble Reed Seed

Here's were you get to the potentially tricky part of this build: getting your hands on a Thimble Reed Seed.


Thimble reed can be found in the slime biome. (Which I think is officially called the marsh biome or the swamp biome, but if you call it that none of us will know what you're talking about.)

The slime biome has tiles that are infested with slimelung germs. Before you go digging around in the slime biome check the Germ Overlay, the germ icon in the top right (or press F9). Then try to find a way to get at some thimble reed without digging up any slimelung-infested tiles.

If you accidentally dig up some slimelung it isn't a big deal. Slimelung germs die slowly in oxygen or quickly in hot or cold areas. So for instance putting the slime in a storage bin in an ice biome will kill off the germs.


Thimble Reed (on the bottom). The green stuff is slimelung. The pink stuff is "Floral Scents" from the Buddy Bud flower (second from the left). Slimelung: bad, floral scents: good (except for dupes with the Allergies trait).


Polluted water disposal. Thimble reed will happily rid you of all your polluted water.

As for how to get your hands on reed fiber, there are a few options:

  • Digging up a reed fiber plant will give you a seed

  • You can uncover seeds buried in tiles that look like they have cracks in them (that say there is a buried object in them)

  • When a dupe harvests a reed fiber plant there's a chance it will drop a seed.

One thimble reed is enough to get you started, but as you grow your dupe count you will eventually need to add more to keep up with your polluted water production.

You can just keep an eye on your polluted water tank and see if the level is rising. Then add another hydroponic farm tile with a thimble reed seed when needed. And there's no harm in planting more than you need.

(Alternatively you can do some math. Thimble reed consumes 160 kg of polluted water per cycle. One visit by a dupe to a toilet and sink produces a combined 16.7 kg of polluted water. A full-length, 30 second shower produces 30 kg of polluted water. If my brain is caffeinated enough, that works out to about one thimble reed per 8 dupes without showers and one per 3 dupes with showers. But I might be wrong.)

The long-term plan

The final phase for dealing with toilet water is to build a chlorine-based decontamination setup that cleans the polluted water from bathrooms and showers and feeds the water back to into the loop.

As long as you aren't running low on water, some reed fiber production is a good thing. If you are low on water, you can skip ahead to the part of the guide where I cover the decontamination build: Recycling Toilet Water. (There's also a section on Getting (more) water.)

  • Ladders are fine and all, but is dupe life even worth living without Fire Poles? (Rhetorical question - of course not!)

  • Fire Poles allow your dupes much faster movement when going down. (Dupes can climb up Fire Poles if needed, but it's very slow going.)

  • The Fire Pole is unlocked in Refined Renovations in the Solid Material branch of the research tree. Once researched, it is found under Home.

  • There is no right or wrong time to unlock them. But they save your dupes lots of travel time, so I always get them early on.

Tip: Weeeeee! (aka the Fire Pole)

Polluted water bottles


With toilets and sinks built, you can deconstruct your outhouses and wash basins. This will result in polluted dirt and polluted water bottles.

(If your wash basins have been going for a while, they will already have produced some bottles of polluted water on the ground nearby.)

Polluted water bottles emit polluted oxygen, so you might as well not have them lying around if possible. With some plumbing basics researched, you can now get rid of them.

To do this, set up a system to dump the polluted water into your polluted water reservoir. This can either be a temporary setup you deconstruct after you're done or a permanent place for dupes to also dump any future polluted water bottles. If you make it a permanent thing, add a sink so dupes will wash their hands as they leave.


Bottle Emptier

The idea, as shown in the picture(s) below, is:

  • build a Liquid Pump (under Plumbing)

  • build a tile on either side of the pump. (For improved airflow use Airflow Tiles - unlocked in the Gases research branch - but it also works with regular tiles.)

  • On one of the tiles, build a Bottle Emptier (under Plumbing) that empties onto the liquid pump.

  • Connect the pump to your polluted water reservoir.

  • Connect the pump to your power grid.

  • Set the Bottle Emptier to "Polluted Water" (I also raise its priority to 6).


Temporary setup. A liquid pump with a tile on either side. A bottle emptier. Connect the pump to your polluted water network and your power grid. All set!


Permanent setup. I have experimented with different designs for this room over the years but have never come up with one I'm really happy with. This is what I'm using these days, it combines composts and a polluted water disposal. (The thing on the airflow tile to the left of the pump is a deodorizer. We'll cover them soon.)


Disinfect commands

Dupes get germy from carrying germy things - like germy water bottles and germy dirt.


When dupes carry the germy water from your deconstructed wash basin to your dumping station they will spread germs along the way. So when they have emptied out all the polluted water bottles you'll need to do some disinfecting.


  • You can check your germ situation with the Germ Overlay (icon is top right, or press F9).

  • Send germy dupes past sinks to wash their hands. To do that, click on the dupe and use the Move To command.

  • ​To disinfect your base click on the Disinfect icon on the bottom right (the picture of a cleaning bottle). Then click & drag to select your whole base.

​Nothing happening? If no dupes start disinfecting, you can either raise the priority of the disinfect commands or raise the Tidying priority of one or more dupes.

Tip: zooming (even farther) out

  • Press ALT + S to enter screenshot mode.

  • In this mode you can zoom farther out than in normal mode.

  • Press ALT + S again (or press Esc) to return to the standard view.

Polluted oxygen




Polluted water - including bottles of polluted water - emits polluted oxygen (unless the air pressure is very high).


Check the Oxygen Overlay (top right or F1) and you are likely to see some areas of polluted oxygen. Let's clean them up.

Thankfully, this is no big deal - it can be done with Deodorizers. They are unlocked in Decontamination in the Gases branch of the research tree.

​When you have them researched, put them in areas with polluted oxygen. (You can delete them once the air is purified.) When placing deodorizers, keep in mind that polluted oxygen tends to move a bit from side to side, but not really up and down.

Deodorizers require sand and a small amount of power, so remember to connect them to your power grid.

Tip: heat and food

  • It might not seem like it when you first start playing, but heat has ended many a game of Oxygen Not Included.

  • The way heat usually gets you is your food: Mealwood and Bristle Blossoms stop growing at temperatures above +30 C.

  • When you get your hands on late-game cooling technology you will be able to laugh in the face of heat. Until then you need to be somewhat cautious of it.

  • Machines and such generate varying amounts of heat. You can see the amount something generates under Heat (in the build menu or by clicking on it).

  • The amount of heat generated is given in DTU/s. I have absolutely no idea what that is. But comparing buildings will give you some idea, e.g.:

    • a Ceiling Light generates 500 DTU/s

    • a Coal Generator generates 9 000 DTU/s


  • Try to keep buildings that generate significant amounts of heat a fair distance away from where you grow food.

Power 2: coal genratr and transformer


The hamster wheel is adorable but takes a lot of dupe time. Also, you will eventually need more power than a hamster wheel can provide.

You can free up dupes for other tasks and have more power available in your power grid by upgrading to coal power. (If this seems intimidating, don't worry - you'll have it up and running in no time.)

And this is what we're building.


Basic coal power. The coal generator generates power, the battery stores it, the power transformer protects the power network from overloading.


Coal Generator


Power Transformer


Large Power Transformer

Let's cover some buildings and concepts.

Coal Generator basics

  • The coal generator uses coal to generate power

  • As byproducts it generates heat and carbon dioxide.

  • Each coal generator can generate 600 W of power. (By comparison, the hamster wheel can generate 400 W.)

Wire overload basics

  • ​The basic wire you have been using so far can handle up to 1000 W

  • At power use of over 1000 W the wire will overload and start taking damage

  • After taking sustained damage a wire section will break and need repairing by a dupe


Power wires only overload through buildings and machines using too much power, not through lots of power being available on a power grid.

Meaning, you can have lots of coal generators hooked up to your power grid without doing any damage to power wires. The central issue isn't how much power your power grid can produce, but the total amount of power actually used at any given time.

You can design your power grid so that wires can't overload. This is done with the help of power transformers.

Power transformer basics

  • A power transformer limits how much power machines that are connected to it are allowed to draw from the power grid

If buildings and machines on your power grid need more power than a transformer will let through, then you will have a brownout. Meaning some machine, or machines, won't run. But your power wires won't overload.

At some point you will want to have more machines running than a single power transformer can supply power to. This can be done by splitting your power grid into several smaller sections, each connected to their own power transformer.


Multiple power transformers. Each grid is allowed up to 1000 W, so all three jukebots can run at the same time.

  • There are two things to keep in mind:

    • How much power the various buildings and machines in your base can consume.

    • how much power your wires can handle.

  • Remember that not all power consumers are active all the time. A water pump uses 240 W when pumping water but 0 W when idle.

  • There are two main kinds of power wire you will use to connect stuff in your base. They have different upper limits before overloading:

    • Wire: 1000 W

    • Conductive Wire: 2000 W

  • You can use power transformers to limit how much power a wire is allowed to draw from your grid. Machines that would send a wire over the transformer's limit will not get power.

  • There are two different Power Transformers

    • The Power Transformer lets through 1000 W

    • The Large Power Transformer lets through 4000 W

  • The Power Transformer pairs nicely with standard Wire - both have upper limits of 1000 W.

  • Note that the Large Power Transformer will allow a draw of up to 4000 W, which is more than the 2000 W the Conductive Wire can handle before overloading. So you need to keep an eye on your potential power consumption, using the Power Overlay (icon in upper right or press F1).

  • The general approach is to use heavi-watt wire (or conductive heavi-watt wire) to connect power generators to batteries and power transformers. And then use wire (or conductive wire) from the transformers to your machines etc.

Tip: power - power transformer and wire overload basics

With the lecture out of the way, let's get to the building.


You will need three research unlocks, all in the Power branch of the research tree (found at the top, under Food):

  • Power Regulation

  • Internal Combustion

  • Advanced Power Regulation


The required research.


Heavi-Watt Wire


Heavi-Watt Conductive Wire




Conductive Wire

When choosing a location for your coal power plant, keep in mind that it generates both heat and carbon dioxide. That said, this is a small setup and can be built in a temporary location.

  • Build a Coal Generator

  • Build a Jumbo Battery

  • Build a Power Transformer

  • Using Heavi-Watt Wire, connect the Coal Generator(s), Jumbo Battery and Power Transformer

  • Using Wire, connect the Power Transformer to the existing Wire network in your base.


Since your coal generator will need coal, you can put a storage bin nearby and set it to only accept Coal (found under Consumable Ore).

Without automation your coal generator will run day and night, even when your battery is full. This isn't a big deal over short periods of time, but sooner or later you should get around to automating it. (Again, don't be intimidated - it sounds more difficult than it is. And there's a separate guide, Getting started with automation, in which I walk you through it.)

Oh, and with this new source of easy power, if you haven't yet built a Refrigerator this might be the time. (Unlocked through Agriculture in the Food research branch.)

​A note on power transformer connections

Power transformers have two connection points. The upper one is for incoming power from power producers, the lower one is for power going out to consumers. (One way to remember which is which: look at the arrows on the transformer. A lot of power comes in by the big arrow, a little power goes out by the small arrow.)

A note on battery placement

Place batteries on the Heavi-Watt Wire side of your power grid. Basically, anything that produces or stores power is connected to Heavi-Watt Wire.

  • On the upper right of your screen you will see a dropdown option that says "Resources" and a smaller text that says "See All."

  • Click on See All to see a list of all the resources you have discovered so far.

  • By selecting resources from that list, they will be added to your screen, showing how much you have of those resources.

  • Use this to keep track of any resources you are interested in. A particularly important one is algae, as that is what we use to produce oxygen. We are also interested in coal, as we need that for our coal generator(s).

  • Coal is under "Consumable Ore"

  • Algae is under "Organic"

Tip: keeping an eye on resources


Dupes exhale carbon dioxide and certain machines (like the Coal Generator) produce it. You can get a better view of carbon dioxide levels using the Oxygen Overlay (icon in the top right or press F1).

When carbon dioxide levels rise up into your base, dupes will have to run up into the oxygen layer every so often to gasp for air. So having a machine (or worse - a bed) in carbon dioxide isn't great.

Dealing with carbon dioxide

Oxygen Overlay. Carbon dioxide is starting to build up. The new Coal Generator will only make things worse.

There are two approaches to carbon dioxide buildup in your base: Deal with it later and Deal with it now.

Deal with it later

Since carbon dioxide is heavier than oxygen, you can postpone solving the problem with a carbon dioxide pit: basically just a ladder going down, with a few tiles dug out around it.

On some maps a carbon dioxide pit will be easy, on others a bit trickier. In the example base the guide pictures are from there is a lot going on at the bottom of the map. There is a lot of water, there is a slime biome, and a cool steam geyser that all need to be taken into consideration when digging out an area for carbon dioxide to flow into.


Carbon dioxide pit. The basic idea is to give carbon dioxide more space to pool underneath your base. The picture shows two possibilities for this: digging out an area around the coal generator and digging a ladder further down under the base.

If you build a carbon dioxide pit, you can extend the ladder further and further down as carbon dioxide piles up in your base. But digging deeper and deeper will become slower and slower as dupes need to hold their breath for longer and longer as they go further and further down to dig.

​Deal with it now

Later in the game there is some limited use for carbon dioxide. (It can be used to power an early rocket in the Spaced Out DLC and it can be fed to slicksters, a kind of critter in the oil biome.) But now let's just get rid of it. We'll do this with a carbon skimmer.


Carbon Skimmer

Carbon skimmer basics

  • The Carbon Skimmer is unlocked through research: under Air Systems, the second step in the Liquids research branch.

  • The carbon skimmer uses water as its input and outputs polluted water.

  • (Though polluted, the water is germ-free.)

  • The carbon skimmer only gets rid of carbon dioxide - it does not produce oxygen.

To make life easier for ourselves, we'll also add a water sieve to the mix.


Water Sieve

Water sieve basics

  • The water sieve is unlocked by researching distillation in the liquids branch of the research tree.

  • It has an input and an output for liquids: it takes in polluted water and turns it into water

  • It uses sand to function, and generates polluted dirt

  • Note that the water sieve does not remove germs; if you input germy polluted water you will get water with germs in it


With the two machines covered, the goal now is a self-contained loop including a carbon skimmer and a water sieve.

  1. The carbon skimmer uses water to get rid of carbon dioxide, and produces polluted water

  2. The polluted water is sent through the water sieve that removes the pollution, turning it back into water

  3. The water coming out of the water sieve is sent back to the carbon skimmer - and the loop starts again from the beginning

We'll look at pictures of the build and how to build it soon, but first some  thoughts on placement.

Carbon skimmer placement

The carbon skimmer will define the point where carbon dioxide buildup ends and oxygen (or chlorine, if any has gotten into your base) begins.

When deciding where to place your carbon skimmer, one option is to put it at the bottom of your base. (Or to dig down to what you think will be the bottom of your base once you're done expanding.)


Another option is to put it further down your ladder network. You will eventually want to dig down to the oil biome (but don't go there without Atmo Suits! - we'll cover them later) and other biomes below your starting biome. A carbon skimmer further down a ladder network will ease this exploration.

And now on to the building. Here's what you're aiming for:


Water sieve and carbon skimmer


Plumbing overlay. Connect white to green and green to white.


Power. Both machines use 120 W when active.

Any time you connect piping you have a good chance of misconnecting piping. So let's go over it.

  • The Carbon Skimmer uses water and outputs polluted water.

  • The Water Sieve uses polluted water and outputs water.

So we connect the Carbon Skimmer output (the green bit) to the Water Sieve input (the white bit).


Then we connect the Water Sieve output (the green bit) to the Carbon Skimmer input (the white bit).

Almost done. Now we just need to add the final element: water.

If you have water near your carbon skimmer you can build a pump in the water. Or if you have water being piped up to your base nearby then you can extend a pipe from your main water line.


If you don't have water nearby, you can set up a simple, temporary solution to dump in some water.


Just add water. A temporary setup to get things going. The Liquid Bridge at the end is to stop the system from overfilling.


All set. The carbon skimmer will slowly rid the base of carbon dioxide. Airflow tiles in room floors help with gas flow. (And fire poles being built.)

The above pictures show such a temporary setup:

  • A liquid pump (powered) with a tile on either side to keep the water in

  • A bottle emptier that empties onto the pump

  • Water passes straight through a water sieve, so if you are dumping water into the system then you can connect the pump to either of the pipes. If you are dumping polluted water into the system, it has to be connected to the water sieve input pipe.

    • For this connection, use a Liquid Bridge for the final connection.

    • The white end of the liquid bridge should connect to the pipe coming from the liquid pump

    • The green end of the Liquid Bridge should connected on to the pipe leading to the carbon skimmer input (white) pipe.

  • The Bottle Emptier is set to water and - IMPORTANT: click on "Enable Auto-Bottle"

On Enable Auto-Bottle

Without this enabled, dupes will only be allowed to empty bottles already lying around your base. Enable Auto-Bottle lets them also get water from a pitcher pump to empty in the Bottle Emptier.

On why there is a Liquid Bridge in the build

The reason for the liquid bridge has to do with how liquids and pipes work in Oxygen Not Included.

The Liquid Bridge works such that it will only allow water to pass over it if there is space in the pipe it is connected to. Liquid bridges are useful to avoid over-filling a pipe network.

Once the system is primed - when there is water running in our infinite loop - you can deconstruct the temporary setup.


On deconstructing pipes

Deconstructing pipes with liquid in them will cause the liquid to spill out. You can empty liquid from pipes (into bottles on the ground), but this requires the Plumbing skill - two skill points spent in the Tidying skill tree.

Sand and composts

The Water Sieve needs sand to purify water, and produces polluted dirt in the process. So it is a good idea to have a Storage Bin somewhere nearby, set to store sand (found under Filtration Medium).

You can also put a Compost nearby to deal with the polluted dirt. Or you can have your dupes run it up to some other compost. (Or you can just ignore it. Which seems wrong, but is also entirely possible.)

  • All those resources you dig out? When they are lying on the ground (or worse: the floor of your base) they aren't just resources - they're debris.

  • Debris has a negative decor value. You can see decor with the decor overlay, the cactus icon in the top right (or press F8).

  • To keep your dupes happy and stress-free, you want to keep their morale up. And, as you probably guessed, debris is bad for morale. (But not actually a huge deal, so don't worry too much about it early on.)

  • At some point you will want to clean up the debris around your base. There is no right or wrong time to do this - some do it early, others wait 50 or 100 cycles.

  • Of particular importance are places where dupes spend a lot of time. So bedrooms are a good place to clean up first.

  • There are two main options for cleaning up:

    • Storage bins

    • The automatic dispenser

  • The automatic dispenser is like a storage bin, except it doesn't store things. (So it isn't that much like a storage bin, really). Instead, it dumps debris on the tile next to it.

  • The Automatic Dispenser is unlocked in Smart Storage in the Solid Material research branch.

  • The automatic dispenser has a power socket, but you don't need to power it if you are just having dupes dump debris in it.

  • The downside of an automatic dispenser is that the resources on the ground count as debris. The upside is you can gather an endless amount of resources on one tile. Also, if your computer is struggling to keep up, having all your resources in one tile can help with performance.

  • Remember, whichever you use, that you need to set what categories of things to accept.

  • To designate debris to be cleaned up, select "Move debris into storage" (bottom right, or press "K").

  • You can set Storage Bins and Automatic Dispensers to "Sweep Only". Then they only accept materials that you have selected to be swept.


  • NOTE: With an automatic dispenser you may need to set it to Sweep Only, otherwise you will create an infinite loop: dupes keep picking up and storing the same material that the dispenser keeps spitting back out. (Unless you are dumping things somewhere dupes can't reach them.)

  • If necessary, you can also use storage bins to gather lots of stuff in one place.

    • Set it to sweep only and to accept all materials

    • Issue your sweep command

    • Whenever the Storage Bin fills up, empty it (by deselecting all contents)

    • Then just start again from the top, until all sweep commands are taken care of.


Storage options. The automatic dispenser (on the left) dumps stuff on the floor next to it.

Tip: cleaning up Debris - Storage Bins and the Automatic Dispenser

Bristle Blossoms


You may have noticed a lot of activity around your Mealwood. That is because Mealwood needs to be "fertilized" every cycle. In practice, that means dupes need to supply dirt to the Mealwood.


You don't need to worry about your dirt levels for a very long time, but If you continue with Mealwood as your only food source you will eventually run out of dirt.

One option is to switch to Bristle Blossoms, which only require water. Though then you will instead need to keep an eye on your water supply, and will eventually need to tap into a geyser to fill up your water supply. (See Getting (more) water for an introduction to water geysers.)

  • Bristle Blossoms need light and water to grow

  • They will not grow in temperatures above +30 C

Switching to Bristle Blossoms is in no way a necessity. But, if you have the water (and a little bit of power) to spare, it is a way to save dirt and dupe time.

There is a special tile, the Hydroponic Farm tile, that allows us to pipe water directly to whatever is planted in it. With those tiles and a light source, all our dupes will have to do is harvest the Bristle Blossoms when they are ready.

  • The Hydroponic Farm tile is unlocked through Agriculture in the Food research branch

  • The Ceiling Light is unlocked in Interior Decor in the Decor research branch. (You probably have it already.)


Bristle blossoms and the ceiling light. A ceiling light five tiles up can light up nine bristle blossoms, at 4 tiles up it can can light up seven.

How many Hydroponic Farm tiles your ceiling light can cover depends on how high up you place it.

  • If you have a four tile high room, a ceiling light will cover 7 tiles: the tile under it and three on either side.

  • If you have a five tile high room, a ceiling light will cover 9 tiles: the tile under it and four on either side.

  • NOTE: A ceiling light will not offer sufficient light if you place it six tiles up.


If your room is 18 tiles wide, a five tile high room means two ceiling lights can cover the entire floor.

(You can also use a light called a lamp to light up bristle blossoms. It stands on the ground rather than hanging from the ceiling. Whatever fits your design best.)

Bristle Blossoms produce Bristle Berries. Dupes can eat them as such and they can also be cooked into Gristle Berries, which increases both the calories and quality you get from your Bristle Blossoms.

If you have access to Sleet Wheat then, combined with Bristle Berry, you can make Berry Sludge. Berry Sludge is a good meal, but the really amazing thing about it is that it cannot spoil. This makes it an excellent source of food for rocket journeys (in the DLC).

Another option for upgrading to something better than Mealwood is critter ranching. Critters drop meat when they die, which can be turned into barbecue. Critters aren't as fussy about heat as plants are, and they don't require water. There is a separate guide if you want to learn about critter ranching.




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