There are currently 3 types of liquids: water, lava, and honey. While each has varying properties, all of these liquids share common "liquid mechanics" that describe how they move and interact with their surroundings. For example, all liquids flow to fill the area they occupy, and they can all be moved with certain items. Liquid can be dangerous because the player will fall into them and if the liquid is deep, they will drown. However, all liquids are useful to some extent because they can be used in crafting, and this is one of the main distinctive feature between the types of liquids.
Flowing and moving
Liquids can fill part or all of a tile, and can flow between tiles. Liquid in motion is considered "flowing", and can visually occupy more of a tile than it will when it comes to rest. Liquids that are not moving are considered "settled": at each game startup, all flowing liquids are explicitly settled, moving them to their natural destination.
Water flows most quickly, lava is slower, and honey flows the slowest. If a liquid block is placed with open space beneath it, it will flow downwards. If it has a block below it, but open space to either side, it will flow to either or both open sides, resulting in partial tiles of liquid. However, there is a minimum depth for liquid tiles; if the liquid spreads too thinly, it will disappear altogether.
When using a bucket on liquid, the game checks a 3x3 square around that tile for more liquid of the same type. If it finds at least half a tile of liquid in that area, the bucket collects what is there, up to a full tile at a time. Regardless of if it collected less than a full tile, the bucket is always filled completely and is able to pour out a full tile. Full buckets can be stacked up to 99, and placed in inventories, chests, etc. like any other item.
Pumps are mechanisms, used with wires and various triggers. When an Inlet and an Outlet Pump are connected with wire and triggered together, they will transfer up to four tiles of liquid from inlet to outlet. They cannot duplicate liquids, but they can be used to keep a liquid continuously flowing. For moving large quantities of liquids, pumps can be set up once and left to finish the job. (This also applies to filling large areas.) However, the setup can be finicky, it requires a timer, and using a stack of 99 buckets may in fact be more efficient.
Before version 1.4, flowing liquids would tend to increase in volume. They could be purposely poured over blocks to split their flows, maximizing the volume increase, and/or pumps could be used to keep them flowing (and increasing) indefinitely. See below for more details.
Interactions with blocks
Liquids cannot be placed in a tile containing a block, even if the block has been hammered into a partial block. If a liquid tile is adjacent to the empty part of a partial block, it can appear to fill the space, but is not considered "in" the block's tile, and cannot be picked up from there. Blocks can be placed in liquid (except lava). Any liquid in the tile will be trapped, and cannot flow out (or otherwise be interacted with) until the block is removed. However, such trapped liquid can "fall" out of the block during the next game startup, as part of the "settling liquids" phase. As liquids flow, their volume tends to increase. This can be exploited to duplicate liquids indefinitely (see Infinite Liquids below).
If a full tile of liquid is next to a half block with open space on the other side, it will visually flow over the block and continue as a river or waterfall (including lava or honey). This waterfall is purely a visual effect, and cannot be interacted with (a "lavafall" of this sort will not burn the player, nor a "honeyfall" heal them). If the liquid is water and the half-block is a Gemspark Block or Rainbow Brick, the waterfall will glow with the color(s) of the half-block.
At various points in the world, liquids can be found dripping from ceilings. This dripping effect is purely visual, and has no functional use. This effect can be created by the player using Magic Droppers. Natural or player-made "droplets" can be broken (but not harvested) with a pickaxe or drill, aiming just below the block they drip from.
Liquids can be stored temporarily within Bubbles, which are otherwise furniture-like, but displace liquids as if they were blocks. Upon restarting the world, the liquid will be freed, allowing it to fall (it is wise to remove lava from bubbles before exiting the world). Bubbles can also be used to support liquids in midair (again, as if they were blocks), and these will not fall when the world is restarted.
Interaction with players
Players normally cannot walk over liquids, and will instead fall in. Falling into liquid negates all fall damage regardless of distance and depth of the liquid pool. Players entering/exiting liquids will make a splashing sound and appropriate animation. Certain items can allow walking on liquids (see below); the player still will not take fall damage when landing on the liquid. While in liquids, players will find their movement slowed. The slowing effect matches the liquid's flow speed: Water is least restrictive, lava is in-between, and honey is most restrictive.
Players have no natural ability to swim in liquids, but can still jump or fly according to their current equipment. Certain items can cancel the movement penalty (only for water) and/or allow free swimming, see below for details. The Flipper (or its upgrades) will allow the player to swim freely in any direction. However, it does not allow them to float, and as soon as they stop moving they will sink down through the liquid. The Inner Tube causes players to float to the surface. The Neptune's Shell and its upgrades will allow the player to swim freely in water or honey, but not lava. Note that neither landing in nor jumping out of liquid (including swimming up past the surface), will reset flight time for wings or Rocket Boots variants.
A player who stays submerged too long in water or honey, will begin to drown. When the player first goes above neck level in the liquid, the breath meter will appear, and slowly empty. When the meter empties completely, the player will begin to take damage (about 17 health per second without any equipment). When the head of the player emerges from the water, the breath meter will rapidly refill and then vanish. Various equipment can prevent drowning: Diving equipment will slow the emptying of the breath meter. The Breathing Reed will do likewise (and stack with the diving equipment); it also reaches above the player's head, and if the end of the reed is in air, the player can refill their breath meter. A Neptune's Shell (or its upgrades), or the effect of the Gills Potion will remove the breath meter and prevent drowning in water altogether.
There are a few different ways to remove liquids:
- In Desktop version, Console version, Mobile version, and Nintendo Switch version, a Dry Bomb can be used to easily remove any liquids. However, these require lava-fishing to obtain.
- There is a special trick to drain pools of water (only) from beneath (see Water, below).
- If small amounts of one liquid are poured over a pool of another, even a single bucket's worth can solidify much larger amounts (generally at least twice or three times) of the target liquid.
- The Super Absorbant Sponge and Lava Absorbant Sponge can be used to destroy water and lava, respectively. The former is available only from the Angler in Hardmode, the latter requires lava-fishing.
- If a block or so of liquid is poured over a large flat space, it can spread to the point where it dissipates entirely.
Crafting with liquids
When different liquids touch each other, they create one of the three contact-created blocks: Obsidian (water+lava), Honey Block (water+honey) and Crispy Honey Block (honey+lava). When this happens, up to a tile's worth of each liquid will be consumed, but either or both of the touching tiles can be partial and/or flowing tiles – that is, creating the block does not require a "full" tile of either liquid.
All liquids can be fished in. For each liquid, the pool must contain a minimum number of tiles for fishing to work (see the Fishing page for full details). Lava requires a special fishing pole to fish in it, the Hotline Fishing Hook. In the Desktop version, Console version, Mobile version, and Nintendo Switch version, the Lavaproof Fishing Hook accessory or Underworld bait can be used to fish in lava with any fishing rod. Lava and honey have a very limited selection of fish that can be caught in them.
Water is by far the most common liquid in the game, appearing in lakes from the edge of space to the depths of the caverns. (Lower in the caverns, lava takes over as the primary liquid, but some water still appears.) However, if water enters or is placed in the Underworld, it will rapidly evaporate.
- Water does not usually provide any buffs or debuffs, but entering water will remove the On Fire! debuff. In Expert Mode, entering water in a Snow biome will apply the Chilled debuff.
- Pools of water can spawn critters (usually Goldfish) or enemies depending on depth and biome.
- The color of water varies depending on the biome the player is standing in. It can be altered manually with Water Fountains.
- Water Walking Boots, or any of their upgrades, will allow walking on the surface of (non-flowing) water.
- A Neptune's Shell (or any upgrade thereof), or Fishron Wings will almost completely remove the slowing effect of water (only).
- If large amounts of water are poured into the Underworld, (e.g., diverting a lake or ocean), eventually all the water will evaporate, but this can take some time, and it will convert the lava surface to Obsidian.
- There is no way to "melt" ice or snow into water, nor the reverse. Therefore, the amount of Ice Blocks in a world is limited. In a Snow biome, hazardous Thin Ice will spawn on top of the water, but it cannot be taken in any way.
- Water can be produced endlessly with the Bottomless Water Bucket (or see below). The Super Absorbant Sponge can likewise be used to remove water freely.
- A special trick can be used to destroy a large water pool from below (this only works on water): Dig a 2×2 hole a block underneath the bottom (that is, the hole should still be dry). Place a chest into the hole, and put 3 or 4 buckets of lava or honey over the chest. Now dig out the blocks above the chest so that the water can flow in. Since the Obsidian or honey block has no place to form (and cannot break the chest), the flowing water will simply be destroyed.
- If Hellstone is mined in the Underworld, each block drops a half/full bucket/tile of lava. Lava can be farmed by repeatedly placing and mining Hellstone, but only in the Underworld.
- If in Expert Mode, Lava Slimes will drop lava upon death.
Lava has two unique properties: it deals damage, and it dislodges and destroys items. Lava will deal direct damage to the player on contact, and inflict the On Fire! debuff. However, the player cannot drown in lava. The Obsidian Skin Potion or Lava Charm/Lava Waders will prevent contact damage for their duration, and an Obsidian Rose will sharply reduce the damage. Lava's contact damage is reduced by a player's defense, so advanced armor can be helpful. Lava will also burn most enemies, and so can be used in traps.
- Lava is opaque, and will hide both objects and creatures, including the player.
- Blocks cannot be placed in lava, but blocks that are subject to gravity (Sand, Silt, and Slush) can fall into it and thereby be placed at the bottom. This can be used to build a pillar for bridging the lava.
- Lava can only destroy items with a rarity of . These items will be destroyed if submerged in lava past the midpoint of their sprite. There are a few rarity items which are immune to lava: Obsidian, Fireblossom and its seeds, and Living Fire Blocks of any type.
- Flowing lava will dislodge most platforms and furniture, which may then be destroyed as items. Pumps, statues, Obsidian Platforms and Obsidian furniture are unaffected.
- Lava Waders will allow walking on lava indefinitely (if the surface is settled), and even allow swimming in it for 7 seconds.
- Flippers or their upgrades allow swimming in lava, but will not help with the movement speed or contact damage. The Neptune's Shell and its upgrades do not work in lava.
- Lava can be produced endlessly with the Bottomless Lava Bucket. The Lava Absorbant Sponge can likewise be used to remove lava freely.
Honey is the rarest liquid in the game, and is naturally found only in and around Bee Hive mini-biomes inside the Underground Jungle. It can be created by mining Hive Blocks, but if honey is produced, the Hive Block will not drop. Honey will slow the player's movement a great deal (as will the Honey Blocks often found nearby).
- Honey is nearly opaque, hiding submerged items and creatures.
- Honey pools will provide the player with a special life regeneration buff. This effect lasts as long as the player is standing/swimming in honey, then another 30 seconds after they leave the honey. The player does not need to be submerged, but the honey pool must be at least two tile's worth, and not too shallow. There are also a couple of healing items to be produced at honey pools, namely Bottled Honey and Honeyfins.
- Like water, the player will drown in honey if submerged for too long. The same items that slow or prevent drowning in water, will do likewise in honey.
- The same items which allow walking on water (Water Walking Boots or any of their upgrades), or swimming in water (Neptune's Shell or Flippers, or their respective upgrades) will work the same in honey. However, they will not prevent the slowing effect of honey (Fishron Wings will however).
Using pumps, a player can construct infinite liquid sources, by pumping liquid in a continuous cycle.
To the right are two examples of compact infinite liquid factories, with arrangements to produce the contact blocks as well. Note the enclosed storage to prevent overflowing and the 1 Second Timers to automate the process. The first uses a common mixing chamber that can draw fluid from the generation chambers, four tiles per switch-press. The second takes an alternative approach to have blocks continuously available.
The second option's double Outlet Pumps do not (as formerly thought) duplicate the liquid from the input. However, they may still help speed, by carrying overflow liquid when the first Outlet Pump is blocked (that is, the liquid it brought in last cycle has not had time to flow away).
In 1.4, the above form of liquid generation has been disabled; the liquid generators above will not work well, and may destroy liquid instead of creating it. There are however new alternatives:
- For Water and Lava, there are "bottomless buckets" available. The Bottomless Water Bucket and its reverse item, the Super Absorbant Sponge, are Hardmode Angler rewards; while the Bottomless Lava Bucket and its reverse item, the Lava Absorbant Sponge, are caught directly while fishing in lava.
- The alternate method, which works for all three liquids, again involves fishing in lava for Obsidian Crates or Hellstone Crates; these can also contain Wet Bombs. These will create water when they explode, and they can be hand-crafted into Dry Bombs, which remove (any) liquid where they explode. These in turn can be crafted into any of the three liquid bombs, when the player is standing near the respective liquid (this does not use up the liquid). This provides Lava Bombs or Honey Bombs (and lets a Dry Bomb be converted back to a Wet Bomb).
- The Demolitionist will sell Wet Bombs, Dry Bombs, Lava Bombs, and Honey Bombs as long as they player has the given type in their inventory, allowing for as much liquid as the player can purchase. It is wise to set aside one of each of the four types (or at least a Dry Bomb) to make sure of having one available when buying more.
- The Cyborg will sell Dry Rockets, which can be crafted into Wet Rockets, Lava Rockets, and Honey Rockets while standing near the respective liquid (similar to Dry Bombs). It is important to note that these Liquid Rockets explode immediately on contact with liquids.
- Desktop 220.127.116.11: Updated fishing loot, such as crates and lava fishing rewards.
- Desktop 1.3.4: Liquids flow more dynamically and have a new option to configure this behavior.
- Desktop 1.2.4: Introduced fishing and associated items.
- Desktop-Release: Introduced water and lava.
- Console-Release: Introduced.
- Switch 1.0.711.6: Introduced.
- Mobile-Release: Introduced.
- 3DS-Release: Introduced.