How to Move Water in Sandustry

Water is the input to most of the early game. Sand becomes Wet Sand becomes Gold; Seeds have to be wet before a Planter Box will take them. The official page puts it directly: large volumes are needed for an efficient factory, so you need a plan rather than a puddle.

The three parts

The Pump sits in the liquid and consumes what is in its own tile. Pipes carry it. The Liquid Vent puts it back out. That is the whole system, and each piece has one behaviour worth knowing.

Pipes are completely non-solid. They can be placed in the same square as any other block, and they interact with nothing at all except the Pump and the Vent. You do not need to route around your factory — run the pipe straight through it.

Both ends are 4×4 blocks that only work through their middle. The Pump and the Vent each occupy a 4×4 pixel area, but only the central 2×2 actually moves liquid. The consequence is sharper than it sounds: if the bottom three of the four layers are blocked, the piece stops completely.

More Pumps into one Vent increases output, up to a limit the wiki does not put a number on.

Why yours stopped

Three things stop the flow, and none of them looks like a fault.

The liquid dropped below the Pump. The rule is stated plainly in the Beginner’s Guide: fluid keeps moving as long as there is fluid at or above the Pump. Drain the pool the Pump is standing in and the system stops, having done exactly what it was told. Check this first — it is the one that is easy to see once you look, and easy to miss because the machinery all still looks fine.

The other two are harder to spot.

Something solid fell into the Pump. A Pump is non-solid to every pixel, not just liquids — Gold and Sand drop into it exactly like water does, and once they are in there the water has nowhere to sit. Nothing visibly breaks; the pump just stops carrying anything.

It is also hard to see, because only the bottom of the Pump is even slightly transparent. The official trick for diagnosing it is to hover the Grabber over the Pump and read the tooltip: if it highlights anything other than a liquid, that is your blockage.

The Vent drowned in its own output. The Liquid Vent stops emitting once water — or anything else — reaches its third layer of pixels. So a Vent placed low in the space it is filling will work until the pool it is creating rises past it, and then quietly stop. Put the Vent above the level you intend the water to reach.

Those first and third checks are two halves of one official rule, which is worth holding as a single sentence: fluid moves while there is fluid at or above the Pump and the fluid level has not reached the Vent. Both ends have to stay in range, and a working system can break either end without you touching it.

One liquid per network

Liquids commingle inside the system. Connect two different fluids into one pipe network and whatever comes out of the Vent is a mixture — and the Vent gives you no way to filter it, because it simply emits whichever liquid is nearest.

So keep fluid lines separate at the source — the network itself offers no way to separate them again. The one thing that does sort liquids is the Advanced Filter, and it acts on liquid in the world rather than inside the pipes, so it is a stage you build after the Vent, not a setting on the Vent.

Lava is the exception

Pipes carry every fluid except Lava. That is not a limitation you can engineer around with a different pump, it is a property of the system — moving lava has the freeze, dig, carry and re-ignite cycle that replaces it.

Where water actually comes from

The official page lists four sources, and they are not equal.

Source	Runs out?
Surface lakes and underground deposits	Yes — this is what people run dry mid-game
Melting Ice	Limited by the ice you find
Rain, from Steam reaching the sky	No
Lumlings	No

The rain route is the one to build around, and the loop is documented end to end: the Cryoblaster makes Snow without limit, heat turns Snow into Steam, Steam rises, and Steam that reaches the sky comes back down as rain. That is infinite water for a tier 2 unlock at 1,000 Gold, plus a heat source.

The other endless option is biological. A captured Lumling releases water on a cycle, and critters compares the two — the short version is that the Cryoblaster is available far earlier and the Lumling needs no conversion.

Water behaves like a pixel, not a fluid volume

Two behaviours that catch people out, both official.

Loose droplets evaporate. Water spreads until its surface is flat. A droplet that does not find a depression to settle into within 45 seconds disappears. So water you spray around rather than contain does not accumulate somewhere out of sight — it is simply gone.

Corners leak. Liquids cannot pass through a solid block, but they will slip through the point where two block corners meet if nothing is placed to stop it. A container that looks sealed can drain through its own diagonal joins.

What blocks water, and what does not

Four building blocks stop water flowing: Block, Conveyor Belt, Kinetic Press and Flux Emanator. It passes through everything else — most importantly through Filters, which is why a Filter is never the tool for draining a line. A plain Conveyor Belt is — though a belt is only a floor to water, never a conveyor for it.

The Advanced Filter is the exception, and the only building that sorts liquids at all.

Related

• Sandustry Filters Explained — why a Filter will not stop water
• How to Let Wet Sand Through Without Letting Water Through — the specific case
• How to Move Lava in Sandustry — the fluid pipes cannot carry
• Sandustry Critters — the other endless water source