When placed in open terrain liquid blocks are a source for a flow, unless they are confined by other blocks. A completely confined liquid will render as still.
Source blocks that are at least partly liberated will begin to flow, spreading according to the flowing fluid rules, and will render as flowing, with animated lines demonstrating their direction of flow.
A source block appears as being "full" nearly to the top of its containing blocks (if any) while flowing liquid blocks appear to be "emptier" the further they are from their source.
Flowing liquids exert pressure on entities pushing them in the direction of the flow. Item drops that fall into a flowing liquid are carried along until they get caught in an eddy or the flow reaches its maximum extent. Most mobs are able to float in liquids, so they do not drown, but cannot swim upstream, which makes a liquid flowing into a dead end a useful mob trap.
Liquid blocks are non-solids in the same way that air is so placing a solid into a liquid block, source or flowing, will succeed if placement detects the side of a solid block through the liquid.
Source blocks placed such that they create a waterlogged non-solid block behave as any source block would, with the exceptions noted in the following sections.
Liquid blocks have a depth value that measures how "empty" it is, with a source block having a depth value of 0, so it is full. Flowing liquids have a depth value equal to their source's depth + 1 with a maximum possible "emptiness" value of 7 where the flow stops. Thus a flowing block next to a source has depth value 1, the next further away 2 and so on till the flow stops. The rendering of liquids is controlled by their depth values both in the height of liquid level and the direction of flow displayed.
Once a source block is placed, the liquid spreading procedure begins. It does not matter if the source is placed makes a waterlogged block or is placed into a block of air, both work the same way. This block is the first block on a sort of list of blocks involved in the spreading procedure.
First, each open side of a liquid block starts a flow. A water block in a flat plain will spread out in all four directions until it reaches the depth limit forming a nine-block diamond point-to-point. It also means that a water source floating in midair will flow out to each of its four sides and then down. Each flowing block created is added to a list of blocks to be considered for further spreading.
Now the blocks directly below each source or flowing blocks on the "Spreading List" are checked:
- If that block is air, it is replaced by a flowing liquid block with a depth value of 1 greater than the block just considered. This new block is also added to the "spreading list".
- Else If it is a waterlogged, non-solid block then checking stops as the waterlogged source block has its own "Spreading List"
- Else If the block below is a type of non-solid block that is affected by the liquid then it is (maybe) converted into a dropped item, and is then replaced by a flowing block with depth value 1 greater that the block above and is added to the spreading list. The block above is removed from the "spreading list".
- Else if the block below is a Solid block, or one of a few non-solid blocks (I.E. Fence Posts), that are unaffected by liquids flow spreads out to all open sides, these additional flowing blocks are added to the list.
- Else if it is a liquid block of another type the rules for mixing liquids are considered. If new flowing blocks are created they are added to the list.
- Else if it is a source block of the same liquid then flowing stops.
- Else if all four of the surrounding blocks are solid the spreading procedure stops. This is how one can create a lava or water column that does not spread on the ground.
Flowing liquid has a speed value that governs how fast the spreading effect takes place. Water in the Overworld and Lava in the Nether moves at the same speed of 1 block every 5 game ticks, or 4 blocks per second. However, Lava in the Overworld is much slower than water, and moves at only 1 block every 30 game ticks, or 2 blocks every 3 seconds.
The shape of the ground around a flow is considered when evaluating its spread, giving preference to the creation of water or lava falls, for aesthetic purposes. During the evaluation of horizontal spread, the 5-block area around source and flowing blocks is checked for air one block below the liquid block. These air blocks, and the blocks preceding them, are all converted to liquid blocks with depth level of 1 greater than the current block to establish a simple flow, but are not added to the collection for later consideration.
For example, the flow of water from a single source placed within 7 blocks of an edge will be only one block wide to the edge, and then will fall as a one block wide stream, as demonstrated in the image to the right.
It is possible to take advantage of flowing liquids to form barriers against mobs by paying close attention to the spreading rules
In 1.13, there is something changed on the directional flow of water from a waterlogged stair or banner.[more information needed]
Water normally spreads equally in all directions from a waterlogged block, as seen to the right.
In the same test setup the water flow from a stair or banner is one-directional.
When particles are fully enabled in the options menu, solid blocks that have air below and liquid above will drip, as a visual indication that only one layer of blocks separates the player from the liquid above. Dripping lava does not cause damage or start fires. It can take several seconds before dripping starts.
These actions will cause a liquid block to update:
- Another block is placed into its space
- Liquid starts to flow in from an adjacent block
- An established incoming flow stops
Generated structures never cause block updates to adjacent liquids when they generate. For example, a cave entrance that is created partly below water level at the edge of a body of water/lava will not cause the liquid to flow until it receives a block update. On the other hand, liquids created as part of structure will flow immediately if not completely confined; this includes holes in the bottom of an ocean that open into a ravine below.
When the two liquids interact, the results vary depending on the position of the liquid source.
- If lava flows vertically into water, the water turns into stone.
- If lava flows horizontally into water, the lava turns into cobblestone.
- If water flows horizontally into flowing lava, a hiss and puff of smoke occurs, but nothing changes.
- If water flows vertically into flowing lava, either cobblestone or nothing may result.
- If water flows into a lava source block, it creates obsidian. The lava spring is destroyed in the process, so unlike with cobblestone, obsidian is not renewable with this method.
- If vertically falling water touches a lava source block on any side, obsidian is created - even if the water would not otherwise run into the lava.
|Java Edition Classic|
|0.0.12a||Added water and lava.|
|1.0.0||Beta 1.9 Prerelease||Liquid that is suspended above an open area by one block thick of material will seep through the material and drip to the floor.|
|Lava that falls onto water will produce stone, instead of replacing the water.|
|Beta 1.9 Prerelease 5||A lava block could be converted into a source block if the following conditions were met:
|Beta 1.9 Prerelease 6||Lava source blocks can no longer be created.|
|1.13||18w10c||Changed water physics.|
|18w10d||Water no longer flows through the rearside of stairs.|
|18w19a||Separated some of the logic for blocks and fluids.|
Water and stone.