Water sort: how to play and beat hard levels
Water sort is the puzzle where you pour coloured liquid between tubes until each tube holds one colour and nothing else. It’s been downloaded hundreds of millions of times under a hundred different names — water sort, colour sort, ball sort, nut sort — and under the paint they’re all the same puzzle.
Here’s how it works, how to get better at it, and what to do when a level just won’t go.
The rules
There are only three, and every game in the genre uses them.
- You can only pour the top colour out of a tube.
- It can only go onto the same colour, or into a tube that’s empty.
- All of that colour moves at once, or as much of it as fits.
You win when every tube is either empty or holds one colour. There’s usually no timer and no punishment for a bad move, which is exactly why it’s so easy to lose an hour to.
The strategy that actually works
Most water sort advice comes down to “think ahead”. Here’s what that means in practice.
Empty space is the thing you’re really managing. Every hard level is a puzzle about how many free slots you have. Beginners spend their empty tube on the first move that looks tidy. Good players treat it as the last thing they’ll give up.
Finish one colour at a time. Splitting a colour across three tubes costs you pours you never get back. If you can bring one together, do it, even when it feels like it achieves nothing this turn.
Watch what a pour uncovers, not what it tidies. A move is usually worth making for the colour it reveals underneath, not the neat stack it leaves on top.
Count before you use your last empty tube. The most common way to lose a board is filling it with a colour that has nowhere else to go. Before that pour, check that something can come back out.
The colours at the bottom are the real problem. A colour stuck under three others needs all three to have somewhere to go first. Plan from the buried colours upwards, not from the top down.
Why some water sort levels are genuinely impossible
This is the part most guides skip, and it’s the honest answer to “am I just bad at this?”
Some levels can’t be solved. Not “are very hard” — can’t be solved, by anyone, ever. That happens because plenty of games in this genre shuffle their boards at random and never check them. A random arrangement of colours isn’t automatically solvable, and if nobody checks, impossible boards go out.
There’s a good reason cheap level generators skip the check. Working out whether one of these puzzles can be solved is NP-complete in general — proven for both the water and ball versions in 2022. Checking every level costs real computing time, so a lot of games simply don’t.
So if a level has beaten you for twenty minutes, it’s worth finding out whether it’s you or the level. Our free water sort solver runs in your browser, gives you the shortest set of pours, and — the useful bit — tells you outright when there’s no answer.
Water sort, ball sort, nut sort: what’s the difference?
Almost nothing. The tubes become bolts or hoops and the liquid becomes balls or nuts, but the rules above don’t change, so the same strategy works in all of them. The one real difference is that ball sort usually moves one ball at a time instead of a whole run, which makes its levels longer but not harder.
If a new sorting game looks unfamiliar, check the pour rule first. If it’s “matching top colour or empty tube”, it’s the same puzzle.
A version where the tubes don’t all behave the same
The genre’s one weakness is that every game uses exactly one kind of container. That’s why a single solver beats all of them.
Glasswort is our version, and the twist is that the bottles disagree. A phial is the classic tube: pour from the top. A retort has a spout at its foot, so it fills at the top and empties from the bottom — the first colour in is the first one out. A basin is a shallow dish that takes any colour at all and lets you lift either one, but it’s too shallow to ever finish a colour, so you have to hand it back empty.
Suddenly a colour stuck at the bottom of a bottle isn’t a problem. It’s an opportunity, if it’s the right bottle.
There are 120 levels, and the game solved every one of them before it shipped, so no Glasswort level can be impossible and every target is a real minimum rather than a guess. After that there’s an endless shelf, and one puzzle a day that everybody gets.
It’s free, it runs in the browser, and there’s no account.
Common questions
Is water sort good for your brain? It’s planning practice — you’re thinking ahead and managing what you’ve got. That’s a real skill, though nobody should promise it makes you smarter.
How many levels does water sort have? It depends on the app. The big mobile ones effectively never end: several run to thousands of levels, and add more with each update, so there is no last level to reach. Glasswort has 120 levels with a real ending, and an endless mode after it if you want one.
Is there a way to undo? In most games, yes, and you should use it constantly. Undo costs nothing.