How to play Pipe Flow
A complete guide to the pipe puzzle: the pieces, the one rule, the three levels, how the boards are made, and the habits that connect them faster.
In one paragraph. Water runs out of a single tap and through every pipe that opens onto the one before it. Tap a piece to turn it a quarter clockwise. When the water has reached every piece on the board, you have won. Fewer turns earn more stars, and harder levels earn more points.
The pieces
- Cap - one opening. It is the end of a branch, shown as a round drain that lights up when the water arrives.
- Straight - two openings opposite each other. It only has two positions: up-down and left-right.
- Elbow - two openings at a right angle. Four positions.
- Tee - three openings. Four positions, depending on which side is closed.
- Cross - four openings. Turning it changes nothing, so leave it alone.
Two neighbouring pieces are joined only when both are open towards each other. A pipe pointing at a wall, at an empty cell or at a closed side does not carry the water on.
Playing on Lynxy
- Tap a piece to turn it a quarter clockwise. The pipes the water has reached light up, and the bar above the board counts how many are wet.
- Undo takes back your last turn, as many times as you like.
- Hint turns the wrong piece closest to the tap into its correct position and locks it there, so it is always the next one the water needs. Each turn it makes counts as a move.
- Lock marks the pipes you are sure of. Switch the tool on and tap pipes to lock or unlock them, or simply press and hold any pipe. A locked pipe gets an amber tile and a small padlock, and it ignores taps until you unlock it - so a stray tap cannot spoil what you have worked out.
- Restart scrambles the same board again, from the beginning.
- Sound switches the clunks, bubbles and chimes on or off.
- On a computer, click a piece to turn it, right-click (or Shift + click) to turn it the other way, move between pieces with the arrow keys, play the one in focus with Enter or Space, and undo with Ctrl + Z.
Three levels
| Level | Board | What to expect | Points |
|---|---|---|---|
| Easy | 5 × 6 | About two dozen pipes, mostly long runs and few branches. Some cells are empty, which gives the board its shape. | 1 |
| Medium | 6 × 8 | Around forty pipes with plenty of tees. Nearly every cell is used. | 2 |
| Hard | 8 × 10 | Eighty pipes that fill the whole grid, many tees and crosses, and branches in every direction. | 3 |
Every board is generated
Boards are not picked from a list. When you start one, a generator plants the tap and grows a network of pipes out from it, one connection at a time, until it has covered the right share of the grid for the level. Every cell then takes the shape its connections need - a cap, a straight, an elbow, a tee or a cross - and only after that is each piece turned at random. The board is therefore built from its own solution, so it can always be solved. The number next to Board is the seed: the same number always makes the same board.
Harder levels grow the network more evenly in every direction, which makes more branches; easier levels keep extending the newest pipe, which makes long, winding runs that are simple to follow.
Stars and par
When the board is made, the generator also counts the fewest quarter turns it would take to solve it - the par. Finish within one and a half times the par for three stars, within two and a half times for two, and a solved board is always worth at least one. Undo gives a turn back, so a turn you take back does not count.
Strategy: how to solve faster
1. Start with what cannot be wrong
Look at the edges and corners first. A piece in a corner can only open towards the inside, and a piece on an edge cannot open outwards. An elbow in a corner has exactly one place it can be, and so do tees along an edge.
2. Fix the caps and the crosses in your head
A cross never needs a turn. A cap needs one only if its neighbour is open towards it. Use them as fixed points and work out from them.
3. Work out from the tap
The water has to reach everything through the tap, so the solution always grows from there. Turn the pieces next to the tap so they continue the line, watch where the water stops, and fix that one next. The bar above the board shows you are making progress.
4. Follow the dead ends
A cap that points at a wall must be turned. Every cap needs a neighbour open towards it, and that tells you which way the neighbour must go.
5. Count the branches on Hard
On the larger boards a tee in the middle of the grid has three neighbours that must all be connected to it. Settle the tees first - they decide where the network splits - then the straights and elbows between them follow.
6. Lock what you know, hint what you do not
Lock every piece you have worked out - corners, caps against walls - and the board stops changing under your fingers. When two options look equal, the hint fixes the piece closest to the tap for you.
Frequently asked questions
Is Pipe Flow free?
Yes. All three levels are free, there is no account and nothing to buy. The game is paid for by the advertising described in our Privacy Policy.
Can every board be solved?
Yes. Each board is grown from a working network of pipes and only then turned at random, so a solution always exists.
Can a board have more than one solution?
The generated network is one solution, and occasionally there is another. The game ends when the water has reached every piece, whichever way you got there.
Is my progress saved?
Yes. The board in progress, your undo history, the timer, your points, wins and best times are kept in your browser's local storage and restored when you come back.
Can I play offline?
Once the page has loaded, the game needs no connection - the boards are generated in your browser. Only the advertisement and the measurement need the network.