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[[quoteright:300:[[Literature/TheWonderfulWizardOfOz http://static.tvtropes.org/pmwiki/pub/images/killwithwater01_3793.png]]]]
[[caption-width-right:300:[[JustForPun H2Owned]].]]

->''"Let's see you under pressure."''
-->-- '''[[PungeonMaster Lulu]] casting Waterga''', ''VideoGame/FinalFantasyX''

So you're fighting [[TheJuggernaut an unstoppable behemoth]], and [[TheWorfBarrage everything you throw at it]] just bounces off its skin. You and your companions run, but it's slowly tearing the place apart around you...

...until, in desperation, you throw your bottled '''Water''' at it, causing it to turn to dust instantly. What just happened? [[FramedForHeroism Did something else disintegrate it]]? Was it really a pushover this whole time and you just need to take a refresher course somewhere besides the ImperialStormtrooperMarksmanshipAcademy?

No (well, not only)! You've just faced down an enemy with a rather [[WeaksauceWeakness unfortunate]] KryptoniteFactor, one covering 70% of the planet, and the solution was always just to Kill It with Water.

Unlike KillItWithFire, this strategy doesn't tend to be viable if you're fighting an opponent who doesn't specifically have a KryptoniteFactor to water... ''[[GiantWallOfWateryDoom unless you use an unbelievable amount of it]]'', then it's rather effective. Or you could try [[KillItWithIce making it colder]]. You can even just [[AbsurdlySharpBlade increase the water pressure!]] Or if your enemy is a demon or vampire, then you will most likely need to use ''[[HolyHandGrenade holy]]'' water instead of regular water.

Woe betide someone with this weakness who goes up against a character fond of MakingASplash. Frequently a WeaksauceWeakness, may be counteracted with a KryptoniteProofSuit--usually made out of lead. Could be prevented if [[NoWaterProofingInTheFuture waterproofing existed]]. Can lead to an understandable case of KryptoniteIsEverywhere, because, well...''it's water''.

In video games, this often appears as a manifestation of ElementalRockPaperScissors. Consequently, beings with [[PlayingWithFire an affinity for fire]] are often unfortunately prone to this trope. For when water is merely a deterrent, see CannotCrossRunningWater.



* It seems a lot of [[AliensAreBastards hostile extra-terrestrials]] are [[EasilyThwartedAlienInvasion vulnerable]] to good-ol' H[[subscript:2]]O.
** Like the scraplets, a kind of mechanical pests/parasites who attacked ComicBook/TheTransformers, in the Marvel comic books. Discovered accidentally when a human dropped a glass of water on an infected autobot.
** Sometimes the audience will complain that anything so severely vulnerable to water shouldn't be able to survive in our atmosphere what with all the water vapor. Whether or not they're correct is debatable and as-of-yet impossible to prove.
* In any setting containing monsters that are [[HolyBurnsEvil vulnerable to holy water]] -- vampires, demons, etc. -- a blessing and a Supersoaker are your best friends. True professionals bless rainclouds.
** ''Film/TheLostBoys'' used supersoakers filled with holy water to deadly effect upon the vampires of the movie.
** In ''Film/{{Constantine}}'' [[spoiler: they did exactly something like this: They blessed the water tank of a Sprinkler System. Cue hurt demons...]]
** Also happened in the [[Comicbook/BuffyTheVampireSlayer Viva Las Buffy]] comic book, performed by a drive-in wedding priest no less.
** ''TabletopGame/DungeonsAndDragons'' has a high level spell to bless rainclouds, which combines very nicely with Control Weather.
*** ''Film/FromDuskTillDawn'' pulled it too, with the (former) Reverend blessing super soakers and [[RefugeInAudacity water balloons made from condoms]] for the group to use against the vampiric horde outside their safe room. Proved remarkably (if [[BodyHorror disgustingly]]) effective. The same approach is used in ''Tales From The Crypt: Bordello of Blood''.
* The game of RockPaperScissors is occasionally spiced up with extra hand signs. For example, you can add in [[StuffBlowingUp dynamite]], which [[GameBreaker defeats rock, paper, and scissors]]. The only way to beat dynamite is with water, which loses to ''absolutely everything else''.
* Many accounts of [[MerTropes mermaids]] have them doing this, particularly if they are harmed, harassed, or [[WomanScorned rejected]] by humans. On the other hand, if humans are nice to them, they will usually be quite nice back.

[[folder:{{Anime}} and {{Manga}}]]
* In ''Manga/OnePiece'', Sir Crocodile is made of sand that can freely disperse and reform when struck. When wet however, the sand clumps together so his face can be punched in. Furthermore, ''any'' devil fruit user can be defeated if they can be ''submerged'' in sea water (a problem for a {{pirate}}-themed adventure on a planet with even ''more'' water than the Earth), especially if they are so nasty they don't have friends inclined to help them.
* In ''Manga/{{Bleach}}'', [[spoiler: Lunuganga, the Hollow made of sand,]] suffers of this weakness.
* He isn't killed, but this happens to [[ColonelBadass Colonel]] [[MrFanservice Roy]] [[PlayingWithFire Mustang]] of ''Manga/FullmetalAlchemist'' at least three times over the course of the series. His enemies get him completely soaked, rendering him unable to use his [[FingerSnapLighter ignition gloves]]. HilarityEnsues.
-->''Riza'': Colonel, [[LampshadeHanging you're useless under the rain!]]
** Subverted ONCE when he's soaked and can't use his gloves. [[CrowningMomentOfAwesome Cue him cutting his transmutation circle into his hand, separating hydrogen from oxygen via alchemy and using a lighter to go let hell break loose.]] Justified by the fact that all he needs is his circle and a spark, which is usually provided by said gloves.
* In the manga adaptation of ''Manga/KingdomHeartsChainOfMemories'', this is how Sora, Donald, and Goofy defeat Larxene: Donald casts a Blizzard spell that Sora melts with a Fire spell while Goofy spins them around, creating a sprinkler effect that drenches Larxene and, due to her [[ShockAndAwe electric nature]], causes her to explode.
* In one episode of ''Anime/SailorMoon'', the MonsterOfTheDay is a confectionery-based drone called Marzipan. She easily manages to get the best of the Senshi by encasing them in sweets, until Sailor Mercury manages to attack her with Shine Aqua Illusion. It causes Marzipan to become soggy and heavily weakened enough for her attacks to wear off.
* Very nearly happens to several characters in ''Manga/CardcaptorSakura'' in the episode dealing with the Watery Card. The card spirit itself is also shown to be very tempermental. Additionally, since it is of TheFourElements, it's more powerful than most of the other Card Spirits.
* In {{Amakusa 1637}}, a group of captured {{Japanese Christian}}s is taken to the Unzen Valley. The catch is that there are ''pools of very hot sulphuric water'' in Unzen, so they'll be [[ColdBloodedTorture tortured to death]] there. In fact, [[ActionGirl Natsuki]] and [[TheStrategist Eri]] walk into some jailers already torturing a man like this and attempt to confront them, but the one who saves the day is [[spoiler: [[GadgeteerGenius Eiji Horie]] ]] since he [[spoiler: uses a trick to create the illusion of a rising dragon., which terrifies the superstitious torturers as they believe they've angered the local gods.]] It's actually inspired in a RealLife case; see below.
** Later, this is used in the form of [[spoiler: a DrowningPit where a pregnant woman ''and'' Eiji's love interest, the local HookerWithAHeartOfGold, are locked in. Which is actually the rendition of ''the incident that sparked the Shimabara Rebellion as a whole''.]]
* Used in DetectiveConan, specifically in the case known as [[spoiler: Billionaire Birthday Blues]]. [[spoiler: Years ago, the RichBitch Reika and her UpperClassTwit boyfriend Nikaidou saved themselves from a storm that crashed their boat via basically leaving the RichBitch's childhood friend Yaeko, who had come to help them, to drown in the sea. The guy who was in love with poor Yaeko, Ichieda, decided to take revenge... via murdering the two and using water as his "WeaponOfChoice". In the present he strangles and drowns Nikaido, then he kidnaps Reika and puts her inside a makeshift DrowningPit that he built in a ''deep'' Japanese bath tub, BoundAndGagged so she cannot escape. (As a bonus he drugs Ran and forcibly puts her head inside a water full sink so he can give himself an alibi... which only manages to [[ItsPersonal ROYALLY PISS CONAN OFF]] and give him the first clues needed to take Ichieda down.]]
** Also used in another case, where [[spoiler: another UpperClassTwit, Teruhiko, tried to get away from his soon-to-be UnwantedSpouse Shinobu via drugging the girl and leaving her to die by drowning inside a water park's closed section. [[SnoopingLittleKid The Detective Boys and Conan]], however, found the unconscious Shinobu when they snuck into the spot, and from then on they worked in tandem to both save themselves and Shinobu ''and'' reveal Teruhiko's intentions.]]

[[folder:Fan Fic]]
* Hobbes tries this on the Shadowfax in ''Fanfic/RetroChill'', but [[SubvertedTrope it doesn't work]] - it's actually the weakness of the Blackosts.

[[folder:Films -- Animated]]
* ''Disney/LiloAndStitch'': While water itself isn't deadly to Stitch, he can't swim and is too heavy to remain buoyant even in salt water. Naturally, he winds up on ''the most isolated chain of islands in the world''. [[WesternAnimation/LiloAndStitchTheSeries The series]] shows that Stitch's greatest fear is, in fact, deep water.
** That's not all. Several of his "cousin" experiments could also be nullified through water, although they also needed water to be released from their capsule.
** In TheMovie, from a distance it looks like Stitch's ship is going to crash into the middle of the Pacific, and all the alien races there cheer as they assume he will fall into the ocean and drown. Then they zoom in and see that he manages to make landfall on a little tiny island chain. Much frustration ensues.
* The T-Rex breed of Sharptooth from ''WesternAnimation/TheLandBeforeTime'' are unable to swim due to their tiny arms. [[spoiler: This allowed the heroes to kill the original Sharptooth, drowning him in a lake.]]

[[folder:Films -- Live-Action]]
* In ''Film/TheWizardOfOz'', (in the film version, anyway) The Wicked Witch of the West is really susceptible to death by being splashed with water.
** Parodied in a ''{{WesternAnimation/Futurama}}'' episode: "Who would have thought a small amount of ''liquid'' could ever fall on meeeeee...!" Leela turns herself into a witch a bit later, and meets the same fate almost immediately... due to a [[ToiletHumour backed-up toilet]].
* In ''Film/DarkCity'' John Murdoch kills [[spoiler:Mister Book]] by telekinetically smashing his human host body into and through a water tower, killing the hydrophobic alien within. How a hydrophobic parasite could possibly live inside a being made up of roughly 70% water is a different matter entirely; since they inhabited dead bodies, salt and preservatives may have been involved. Squick.
* In the movie adaptation of ''Film/TheDayOfTheTriffids'', the titular plants dissolve when blasted with salt water. It probably wasn't on the producers' minds, but this is a direct reversal of the original book, in which [[KillItWithFire flame-throwers]] are among the most effective anti-Triffid weapons.
* In ''Film/FreddyVsJason'', Freddy is able to finally break through the unstoppable resolve of Jason Voorhees by tapping into his innate fear of water (brought on by being a drowning victim in life).
* Water turns out to be deadly to the aliens from ''Film/{{Signs}}''. Many consider this plot point to be idiotic: Why the heck were the aliens invading a planet 70% covered in poison, while naked no less? ([[WMG/{{Signs}} We have a few theories.]])
* Another example of water proving fatal to aliens: the blob-like energy aliens in ''Night of the Big Heat'' can't be harmed with bullets or dynamite, but die at the end because their constantly heating the island up to suit their preferred climate [[NiceJobFixingItVillain causes a torrential downpour which melts them]].
* Similarly, drowning was the only way to hurt the (supposedly) NighInvulnerable protagonist of ''Film/{{Unbreakable}}''.
* The villainous monster [[Film/GameraVsBarugon Barugon]] (Not to be confused with [[Franchise/{{Godzilla}} Baragon]]) is killed when Franchise/{{Gamera}} throws him into a lake causing him to drown since water hurts Barugon and he cannot swim.
* [[spoiler: The Kid]] kills [[spoiler: Death]] in ''Film/SixStringSamurai'' with water, realizing his weakness after spitting in his face causes him to scream in pain, as the saliva burns him like acid.
* In the first ''Film/MortalKombat'' movie, [[AnIcePerson Sub-Zero]] is technically killed by a bucket of water tossed at him by Liu Kang. The water reacted to his powers by [[HoistByHisOwnPetard freezing into an ice spear, which impaled him]].
* In ''Film/{{Alien 3}}'', the creature is doused with molten lead, but manages to get out of the foundry; immediately thereafter, he is sprayed with water from a sprinkler system. The resulting thermal shock causes it to explode.
* In ''Film/TankGirl'', [[spoiler: the Big Bad CEO of Water & Power has himself turned into a cyborg with a saw-bladed arm and a holographically-projected face. This makes him nearly indestructible ... until Rebecca dumps water on him and shorts out his circuits.]]
** That technically didn't kill him, just temporarily incapacitate him. [[spoiler:It was her stabbing him with the same dehydration tool he'd use to kill two or three others (on-screen at least) in the movie that did him in.]] So... [[InvertedTrope Kill him without water?]]
* The low-budget horror flick ''Film/NeonManiacs'' features a crew of [[NinjaPirateZombieRobot undead warrior beings]] that are ultimately defeated with buckets, squirt guns, and showers.
* Both monsters in ''Film/FrankensteinMeetsTheWolfMan'' meet their apparent demise when one of the local townsfolk blows up a dam near the ruins where the two are fighting.
* Josiah is defeated in ''Film/ChildrenOfTheCornIVTheGathering'' when he gets hit with water that has been laced with mercury (which is his AchillesHeel).

* In ''Franchise/{{Dune}}'', {{Sandworm}}s are poisoned by water in large amounts. And when killed thus they vomit a toxin that the Fremen Reverend Mothers use to unlock their GeneticMemory and then convert into a drug used in orgies.
* In ''Literature/TheWonderfulWizardOfOz'', a point is made about water being the only thing the Wicked Witch fears more than the dark... and yet she specifically has Dorothy (at this point her slave) cleaning her castle with water... This manages to be even dumber than [[Film/TheWizardOfOz the movie]], where a bucket just happens to be lying around.
** In TheMusical of ''Theatre/{{Wicked}}'', her weakness to water turns out to be merely an urban legend, which she uses to [[FakingTheDead fake her death]].
** In the book version of ''Literature/{{Wicked}}'', she had a bucket sitting around collecting rainwater.
* In Creator/GarthNix's ''Literature/OldKingdom'' series, the Dead and (some/most) Free Magic monsters CannotCrossRunningWater and are destroyed by being immersed. Incidentally, [[KillItWithFire they also are repelled by fire]].
* One of the {{Mooks}} in ''Literature/SkulduggeryPleasant'' uses magic to make himself invulnerable to fire. Unfortunately, it balances out with an ''extreme'' vulnerability to the opposing element...
** Vampires are also somewhat vulnerable to water; ingesting salt water causes their throats to close up, which will probably suffocate them. It is [[LampshadeHanging lampshaded]] that this weakness isn't particularly useful for fighting them. One character is seen to have carried around a vial of saltwater for decades after surviving an encounter in his youth, only for someone to point out that he probably wouldn't be able to get the vampire to swallow the stuff before it finished him off.
* AndreNorton's ''WitchWorld'' series - the Dark cannot (as a rule) cross running water. While this doesn't generally kill them, it can be used to trap them as SealedEvilInACan.
* The various species of [[spoiler: terrestrial mantis shrimp]] found on Henders Island in ''Literature/{{Fragment}}'' are vulnerable to salt-water. Not just vulnerable to it, ''terrified'' of it. However, this could be considered a subversion, as it is not the water itself that kills the creatures, but rather their inability to regulate salt when it is introduced to their bodies. This fact is used heavily in the plot of the story from [[spoiler: explaining why none of these DeathWorld natives haven't gotten off the island and killed us all yet, as well as who sent the emergency signal that brought the boat to the island in the first place and started the whole story]]. One of the character's actually lampshaded this similarity to the Triffids, another group of creatures suceptible to the kill it with salt water tactic.
* One of the "easy" ways to kill a ''Literature/{{Discworld}}'' golem is to [[KillItWithFire heat it to a significant temperature]], then drop a bunch of water on it (or vice-versa), and let the rapid temperature shift work its magic. This happens to [[spoiler: Anghammarad, in ''Discworld/GoingPostal'' during the Post Office Fire]].
** In fact, this is only the second permanent Golem death encountered in the series thus far.
* In the ''EnchantedForestChronicles'', wizards can be (temporarily) melted by splashing them with water, mixed with soap and lemon juice. The discovery was completely by accident, and nobody's completely sure why it works, but it takes all three elements to do the job; in a later story, Prince Mendanbar forgets the lemon, which just results in wet, soapy wizards, until Cimorene reminds him.
** This was discovered by Alianora, Cimorene's fellow (and actually captive) Princess while the two were cleaning. This trope is also reversed when [[spoiler: the Stone Prince throws water on the wizard who is holding the witch Morwen hostage. The wizard melts; Morwen, who practices clean living, does not]].
* The tenth book of the ''Be an Interplanetary Spy'' Literature/ChooseYourOwnAdventure series put you up against a trio of SpacePirates who were, essentially, lethally allergic to water. The end result was the protagonist forcing the leader of the trio to surrender by ''[[CrowningMomentOfAwesome threatening him with a tiny puddle of water]]''.
* In the ''Literature/KnownSpace'' series by Creator/LarryNiven, Martians were spectacularly vulnerable to water. There was a short in which explorers sent to Mars discovered an ornately constructed water well... and realized that it was used as a crematorium. ''That'' vulnerable.
* The Veleek, a nearly unstoppable cloud of dust from ''Literature/{{Animorphs}}'' that can shred any solid matter by touch, is defeated when the kids trick it into falling into the sea.
* In the vampire novel ''They Thirst'', it is eventually discovered that seawater has a deadly effect on vampires.
* From ''Literature/TheDresdenFiles''
** Warden Carlos Ramirez is a water mage and combat magic specialist. In the Dresdenverse, water is associated with entropy and cleansing, and pretty much all of Ramirez's combat spells involve disintegration to some extent.
** [[TheArchmage Senior Council]] [[MagicalNativeAmerican Joseph "Listens-to-Winds"]] is an older and stronger version of Carlos. He once called a rainstorm, by a rain dance, to pour down heavily on a PhysicalGod's magical attacks. The water purified and distilled the magic, nullifying the attacks. He would also simply be untouched as the magic that wasn't destryed missed him or blipped out when it was a foot from him and then started up again behind him.
** The Red Court vampire Arianna used water magic to counter Harry's fire magic during their duel in ''Literature/{{Changes}}. [[spoiler: Which did work until Harry revealed that he, as the Winter Knight, now also could use [[KillItWithIce Ice magic]]. She was quickly [[ImpaledWithExtremePrejudice impaled with dozen of icicles]]]].
* It is strongly implied that in ''Literature/SomethingWickedThisWayComes'', the Dust People might have this weakness. They must leave before the autumn storms because "the rain washes away their dust."
* In IsaacAsimov's ''Rain, Rain, Go Away'', a strange couple melt in the rain, apparently because they were made of sugar.

[[folder:Live Action TV]]
* ''Series/DoctorWho'':
** The titular menace in "The Seeds of Death" is a fungus that threatens Earth until it's discovered that water kills it.
** The fiery Pyroviles from "The Fires of Pompeii" (or the lesser foot soldiers, at the very least) are able to be killed by having water thrown at them.
* In the short-lived UPN series ''Series/DeadlyGames'' (which involved a video game being brought to life, and Creator/ChristopherLloyd being evil), one of the villains (an ex-Quarterback named "Killshot") was burned by water.
* ''Series/PowerRangersMysticForce'' had the utterly invincible lava-based villain Magma. He spent the whole episode effortlessly handing the Rangers' butts to them, and then Madison gets pissed at her lack of screentime (no, seriously) and blasts him with a water attack... which burns him. (However, that's not what kills him - he then goes giant and resumes the buttkicking against the Rangers' HumongousMecha, but is defeated by ''the rules of his own game with the Rangers,'' which must be obeyed even to the death.)
* Used several incarnations earlier in ''Series/PowerRangersLightspeedRescue''; the demons' weakness to water is the only thing that kept them from destroying the [[UnderwaterBase Lightspeed Aquabase]] as early as episode 2.
* The "Frogs" in ''Series/{{Raumpatrouille}}'' can live in vacuum just fine and aren't bothered by energy weapons (at least not the small portable models used by humans in the setting), but ''oxygen'' is lethal to them. This is why they bothered to depressurize the human outpost where they are first encountered instead of simply leaving it as-is, which in turn is what eventually clues the protagonists in to their Achilles' heel.
* In the short-lived ''Series/MisfitsOfScience'', Johnny B. couldn't touch water due to being a living [[ShockAndAwe electrical generator.]] The merest drop burned him.
* In the ''Series/BuffyTheVampireSlayer'' episode "Something Blue," Xander and Anya are attacked by a demon that can only be killed by drowning. They force his head into an inexplicably filled sink, creating smoke and killing it.
** Another episode had Buffy kill a vampire by switching his glass of water with holy water.
* ''Series/DeadliestCatch'', natch. Since the water they are in is near freezing, falling in could cause death within minutes with complete and utter disregard to your ability to swim. A rescue has to happen pretty much immediately, and that is made extremely difficult by the rough conditions of the Bering Sea.
* ''Series/{{Supernatural}}'': demons are highly susceptible to holy water, as you'd expect. One of Bobby's favourite tricks is beer with just a little bit of the stuff - if his visitor is human, they'll never even notice. If they're not, they burn.
** Also, at one point, the boys assault a building full of demons by consecrating the sprinkler system.
* The Newcomers in ''Series/AlienNation'' get acid-like burns from salt water.
** This makes for an ''awesome'' HeroicSacrifice at the end of the movie, when Newcomer George sees his human partner fall into the ocean, and reaches into the water to grab him. In what other circumstances could you reach into acid and pull forth a (mostly) unharmed friend?
** According to those involved in the later TV series, only the sea-salt mixture of SEAWATER had this effect. Salt water using ordinary table salt either had a much reduced or no effect.
** The Newcomers also were kept in their ship for a long time and had built up a natural resistance, like how lungs adapt to higher-elevation living.
* The demon Abaddon from ''Series/TheSecretCircle'' is killed when Diana's father drowns his host body, Nick, at the marina.
* In ''Series/TheOuterLimits'' episode "Specimen: Unknown", an alien plant arrives on Earth. It spreads like wildfire and sprays toxic gas into the air. When it starts to rain, everybody panics and thinks they are doomed, but instead of making the plants grow faster, the rain makes them wilt and die.

[[folder:Newspaper Comics]]
* In one ''ComicStrip/FlashGordon'' story, a portal is opened to an alternate dimension populated with MechanicalLifeforms. They prove hostile and nigh impossible to defeat, until scientists reveal their dimension is "completely dry" - spraying them with a firehose causes instant and lethal rusting.

[[folder:Religion & Mythology]]
* Many elements of European folklore have running water "washing away" magic. This has been incorporated into several fantasy series, and may be the reason vampires are said to be unable to cross running water under their own power.
** TheWildHunt could not cross running water. (Not that this often did much more than delay them. Depending on the myth, you generally needed to get cold iron or survive until dawn, as the hunt could travel to the ends of the earth in a single night, and could afford to take the long route.)
** In Scottish folklore, an unlucky traveler might have to deal with a type of [[EldritchAbomination evil and disgusting]] [[TheFairFolk sea-fey]] called a "nuckelavee" -- a man-like creature that was merged into the back of a one-eyed horse from the waist down (kind of like a centaur, except the horse's head is there too). The best way to escape one of these [[{{Squick}} skinless]] [[BodyHorror abominations]] was to get fresh running water between it and you. Crossing a stream usually worked.
** Possibly one of the more famous Scottish ones is "The Tale of Tam O'Shanter" who, after being discovered by witches has to cross the "keystone of the bridge" in order to escape. He makes it, but his horse gets her tail pulled off. I think the American version of this is Sleepy Hollow, with Ichabod Crane?
* Literature/TheBible uses it a couple of times. [[ApocalypseHow The Great Flood]] and [[CrowningMomentOfAwesome Moses and the parting of the Red Sea]] are rather well known.
* Ireland's Kelpie is a fey that takes on the guise of a black horse and kills people by taking them on a wild ride before drowning them, then eating their livers.

[[folder:Tabletop Games]]
* In ''TabletopGame/{{Rifts}}'', [[OurVampiresAreDifferent Vampires]] can be harmed, even ''killed'' by running water. This apparently means ''any'' water in motion. That means water hoses and squirt guns are effective weapons when vampires attack.
* ''TabletopGame/{{Warhammer}}'' fantasy role-play has a superstition that this is how you kill fire wizards. It doesn't work.
* In ''WitchGirlsAdventures'', this is the biggest downside to having Hag's Syndrome. You can cover up the green hair and skin and red eyes with makeup and the like, but there's not much you can do about your tendency to melt when exposed to water, except avoid it.
* ''TabletopGame/DungeonsAndDragons'' allows you to do damage to undead by throwing bottles of holy water at them.
** In addition, [[OurVampiresAreDifferent vampires]] can be killed by completely submersing them in running water for three rounds (about eighteen seconds)... [[OhCrap unless the creature was naturally aquatic before becoming a vampire, granting it immunity to that particular weakness.]]
* ''TabletopGame/YuGiOh'': The power of the "Mermails'" bracelet is great, with it the "Atlanateans" summoned a downpour, robbing the "Fire Kings" of their power. As well, those who dared to disobey were reduced to bubbles in the ocean…

[[folder:Video Games]]
* In ''VideoGame/KameoElementsOfPower'', water is only harmful to [[ElementalRockPaperScissors fire-based enemies]] and for some odd reason makes the water-based enemies vulnerable (normally they're intangible).
* ''Videogame/FinalFantasyVIII'': the scarce Water magic spells (Water and Leviathan) are weak spots to a handful of enemies. However, fire-based foes are only weak to [[AnIcePerson ice]] magic (Blizzard, Blizzara, Blizzaga, Shiva). Water is also useful early in the game when it is junctioned to offensive stats (Strength and Magic) as it dramatically boosts those stats compared with other offensive magic.
* In ''VideoGame/PrinceOfPersiaWarriorWithin'', water is the Dahaka's only weakness. Finding the [[InfinityPlusOneSword Water Sword]] lets the Prince fight the Dahaka and get the good ending.
* Most of the monsters and bosses in ''VideoGame/SuperMarioSunshine'' are vulnerable to Mario's water sprays.
** Curiously, Yoshis in VideoGame/SuperMarioSunshine disintegrate when in sufficiently deep water, despite not displaying any aversion to water anywhere else in the franchise.
* In ''VideoGame/MarioAndLuigiPartnersInTime'', the invading alien Shroobs are completely eradicated by an absurdly specific type of water: baby's tears. Good thing the Mario Brothers have been spending the whole game adventuring with [[MyFutureSelfAndMe their infant selves]]! An example of [[EasilyThwartedAlienInvasion an Easily Thwarted Alien Invasion]].
* A handful of ''Franchise/{{Pokemon}}'' have some unfortunate type combo of [[PlayingWithFire Fire]], [[DishingOutDirt Ground and Rock]], which makes them 4x vulnerable to Water attacks.
** Subverted with Primal Groudon. While it's a Ground/Fire type that would normally take 4x damage from water, its ability summons Harsh Sunlight that makes ''all'' water-type attacks evaporate.
* Several ''VideoGame/MegaMan'' bosses (usually fire or stone based) are weak against whatever water based attack [[TropeNamer the hero]] [[MegaManning gets from another boss]].
** A notable example is the [[FinalBoss Alien Wily]] in ''VideoGame/MegaMan2'' whose ''only'' weakness is [[NoWaterproofingInTheFuture Bubble Lead]], with every other special weapon actually ''healing'' the boss. The alien is really a hologram, so the ''water''-based weapon shorts out its hologram projector.
* All the vampires in ''VideoGame/LegacyOfKain'' are hurt or killed by water, except for one clan in Soul Reaver that evolved a resistance to it, and Raziel once he acquires their power.
* In ''VideoGame/{{Dominions}} 3'', vampires and vampire lords cannot go underwater by any means. If they do end up in a water province somehow they are killed, permanently. Which can give a player a nice {{facepalm}}-worthy moment moment if he's playing an aquatic nation and summons some vamps for their immortality, only to find out that vampires killed in battle do respawn... in their underwater capital.
* Certain ghosts in ''VideoGame/LuigisMansion'' can only be sucked up if you spray them with water first. Or, alternatively, just drench them until they fade away.
* The Shikigami in ''VideoGame/{{Touhou}}'' are mentioned to be weak against water since it causes them to lose the empowering link they have with their masters. Chen gets a double whammy in this weakness since [[CatGirl she's also a cat]], [[CatsHateWater so she's always weak against water]].
** The Scarlet sisters, being vampires, are weak against running water. In fact, the backstory of the Extra Stage in ''Embodiment of Scarlet Devil'' had [[SquishyWizard Patchoulli]] casting a rain spell to prevent [[PersonOfMassDestruction Flandre]] from leaving the mansion.
* In the ''VideoGame/{{Thief}}'' games, [[TrickArrow Water Arrows]] kill Fire Elementals and can disable the steam-powered Mechanist robots [[AttackItsWeakPoint if aimed at the rear vent]].
* The Endermen in ''VideoGame/{{Minecraft}}'' take damage from water, including rain. An easy way to kill an Enderman fast is to use a Water Bucket on it.
** After the 1.9 update, Endermen have gotten around this weakness with ArtificialBrilliance, any Endermen exposed to water or rain will immediately teleport away.
* In ''Videogame/{{Fallout 3}}'', mirelurks (huge bipedal mutated crabs) in the Jefferson Memorial basin start dying once the purifier is turned on in ''Broken Steel''. Apparently, mirelurks can only survive and nest in irradiated water and die upon prolonged contact with fresh water.
* In ''VideoGame/CastlevaniaSymphonyOfTheNight'', Alucard takes constant damage while too deep in water [[spoiler:until he collects the "Holy Symbol"]].
* In the ''VideoGame/InFamous'' franchise, Cole dies from overexposure to water because it conducts the electricity within him, causing him to electrocute himself.
* In ''VideoGame/TheFiremen'' your fire hose and water grenades are your only means of defense against enemies, which makes sense as all enemies are fire, robots, or flaming robots.
* Rain from ''Franchise/MortalKombat'' weaponizes water. Originally, he could form it into a cohesive ball used in projectile attacks (which let him move his opponent around the arena, oddly), and then in the reboot, he gains a few additional moves with it, and it factors into both his fatalities.
* In ''VideoGame/BioShockInfinite'' the Motorized Patriot enemies are vulnerable to the water-spewing Undertow vigor, which stuns them and electrocutes other enemies near them.
** Further, Songbird is specifically vulnerable to water ''pressure.''
* ''VideoGame/NosferatuTheWrathOfMalachi'': In terms of damage per hit, the Holy Water in the Chalice is the most powerful weapon in the game.
* ''{{Mass Effect 3}}'': The Javelin is a variation of it: Just replace water with ferrofluids (a highly magnetic liquid) shot at very high velocities and you have a sniper that makes for the single most effective anti material rifle in the game since it A. has the highest penetration of all guns. and B. Deals more damage than the Widow. All in all, it is a single shot, high pressured water jet.

[[folder:{{Webcomics}} / WebOriginals]]
* In ''Webcomic/SluggyFreelance'', an army of robotic water coolers is defeated by knocking over their water tanks. Apparently Hereti-Corp never thought to ''[[NoWaterproofingInTheFuture waterproof]]'' their water coolers.
* ''Webcomic/CheshireCrossing'' naturally includes this, but a twist is added where ''any'' witch in Oz will melt when hit by water. Including [[spoiler:Film/MaryPoppins]].
* Averted in a crossover between Webcomic/TheWotch and AccidentalCentaurs with, you guessed it, the wicked witch. No one ever thinks of using water against her. When it IS brought up Lenny points out that she's already used to it, so it wouldn't have worked anyway.
* In ''ThePhoenixRequiem'', shades cannot be killed, but can be subdued by using water.
* The [[CatsAreMean hovercat]] from ''Machinima/WaterHuman'' seems unstoppable, until the protagonist uses his [[MakingASplash water powers]] on it. Then it panics and flees. Because [[DontExplainTheJoke cats hate water]].
* In ''Webcomic/ElGoonishShive'' the best way to beat a fire monster is to [[http://egscomics.com/?date=2010-10-08 punt it into a river.]]
* In the ''{{Nodwick}}'' comics, Piffany's favorite weapon against the undead is her trusty H2Oly Sacred Soaker. She also managed to kill a giant demon with a lake full of holy water.
* In ''AmericanBarbarian'', [[http://www.ambarb.com/?p=369 Rick opts for drowning]].
* Referenced in the "Everything Wrong With" series on ''WebOriginal/CinemaSins''. Whenever this trope pops up in a movie, it's sinned as "X has the same weakness as the Aliens from ''Film/{{Signs}}''." This includes the review of ''Signs'' itself.

[[folder:Western Animation]]
* In ''WesternAnimation/BatmanBeyond,'' water mixed into and diluted Inque's liquid body to the point of her being unable to hold herself together. This was used against her a few times, like her ''WesternAnimation/BatmanTheAnimatedSeries'' predecessor Clayface (though, being denser, it took a while for it to work on him.)
* In ''WesternAnimation/TeenTitans'', Beast Boy discovers that water is the most effective weapon against the BigBad's army of mooks, which turns them into tofu. Cue epic super soaker gunplay!
** Overload was also easily defeated with water at the beginning of "Car Trouble".
** Also, in ''TeenTitansTroubleInTokyo'', they captured Saico-Tek, who attacked their home; during interrogation, he set off the water sprinkler and disappeared. Beast Boy made a joke that he wasn't waterproof, that no one took seriously. It was later revealed that Saico-Tek, as well as the other colorful villains they faced during their visit to Tokyo, were made of ink, [[BrickJoke so he did pretty much get killed by water.]]
* In ''WesternAnimation/InvaderZim'', when Zim is hit by water he screams wildly and his skin gives off smoke/steam with a horrible sizzling noise. It is heavily implied that water acts as an acid to him, if it isn't said outright in the show, and so if Dib ever managed to pour enough water over him, he'd probably melt in a rather horrific fashion. Except that, unlike the aliens from ''Film/{{Signs}}'', Zim quickly discovered a way to waterproof himself once he discovered the weakness, which was to bathe himself in glue.
* In the third ''WesternAnimation/BarbieFairytopia'' movie, one of the guardian fairies' apprentices, the fairy Sunburst's powers are weakened by water. When [[BigBad Laverna]] captures her and takes her place, Sunburst is left trapped inside an underwater bubble until Elina rescues her.
* In ''WesternAnimation/SupermanTheAnimatedSeries'', Livewire's one apparent weakness is water despite the fact that she's supposedly a being of pure energy courtesy of a FreakLabAccident.
* ''WesternAnimation/KimPossible'' has a minor variation on this trope when Dr. Drakken creates an army of Kim clones. It's eventually discovered that the clones are susceptible to ''carbonated water'', prompting Kim to unleash the awesome power of a soda fountain upon the clones.
* ''WesternAnimation/DarkwingDuck'' villain [[PsychoElectro Megavolt]] will short-circuit if splashed with water. Large amounts of liquid (such as Liquidator, a pure water being) effectively knock him out.
** Liquidator himself knows several decent methods of killing it with water, ranging from boiling water to ''water hammer'' to a freaking tsunami. And when he collides with Megavolt...
* [[ElementalRockPaperScissors Waterbenders]] in ''WesternAnimation/AvatarTheLastAirbender'' weaponize water (and sometimes [[KillItWithIce ice]]) quite effectively.
* The Dipper clones in ''WesternAnimation/GravityFalls'', being made of paper, will droop and turn to (nonliving) sludge if exposed to any kind of liquid. They helpfully point this out to the original Dipper as they are totally subservient to him, though this proves more difficult than he expects because of their quantity. The exception is Dipper No. 2, who lives through it all and decides to have a peaceful soda with the original Dipper, forgetting about his weakness.
* In TheSmurfs episode ''The Littlest Witch'' witches are said to loose their magical powers for a year if expose to water.
* Aqualad in ''WesternAnimation/YoungJustice'' has the ability to manipulate water into an assortment of weapons.

[[folder:Real Life]]
* For the most literal way to Kill It with Water, there's always drowning, a danger for all creatures unable to breathe underwater.
* While not killing it with just any kind of water, you can kill a freshwater fish by throwing it in salt water, or a saltwater fish by throwing it in fresh water and watching osmosis happen.
** Before people actually wish to try this, realise one thing: Osmosis is the process of salts and water creating a new balance within cells. Throwing a sea fish into fresh water will make all its cells rupture. [[{{Squick}} His skin and organs will turn into slime]]. A fresh water fish thrown into salt water will die of dehydration. That's how badass osmosis is.
* In the [[ArabIsraeliConflict Yom Kippur War]], the vaunted Israeli "Purple Line" was a series of sand fortifications that faced the Suez Canal. Because it was essentially a gigantic wall of man-made sand dunes, it was considered extremely difficult to breach, especially for a force that would have to conduct an amphibious landing under fire beforehand. In a stroke of genius, the Egyptians blasted it apart with water cannons in under 30 minutes and sent their tanks through the gap, eliciting a MassOhCrap from the Israelis. (Egyptians sometimes cite this as part of their [[NationalStereotypes national myth]] of unorthodox ingenuity, calling it a "very Egyptian solution.")
* [[http://en.wikipedia.org/wiki/Chinchilla Chinchilla]] fur is so thick that it cannot air-dry on its own. If a chinchilla gets wet and is not dried properly, the fur on top will dry and trap the moisture on the skin underneath. While this doesn't lead to death immediately, it opens the chinchilla up to fungus growth, fur rot, and other diseases.
* Most electronic equipment will not survive long contact with water. Just how long varies.
* [[http://en.wikipedia.org/wiki/Water_intoxication Drinking large volumes of water can kill you, actually.]]
** There was the infamous case of a woman in the US who entered a contest named "Hold your wee for a Wii". The purpose was to drink lots of water and hold their urge to pee, but the lady drank too much and she was poisoned with water.
* In a pretty hilarious reference to this trope, a student called for [[http://www.snopes.com/science/dhmo.asp a ban on dihydrogen monoxide]] as part of his science project--and got 43 students to favor the ban.
** Banning "dihydrogen monoxide" has become a very popular petition any time and place there is an abundance of enthusiasm and a lack of information on scientific matters.
* Related to the supernatural examples listed above, graveyards are often built next to a stream, and you can generally tell where the people it was built for lived by crossing over that running water. (iron fences are a secondary favorite)
* If you go down too deep, that oxygen tank on your back won't do you any good. Water ''pressure'' will kill you. Water has weight, and enough of that weight can and ''will'' cause injury or death to anything unfortunate enough to be exposed. Except for inanimate objects, and only on the technicality that they're not alive and are thus damaged or destroyed instead.
** The means by which pressure kills you isn't really obvious, though. If you multiply the surface area of the human body by atmospheric pressure, you'll find that the total atmospheric force exerted on a person is about 40,000 pounds. This doesn't hurt us a bit, though, because the pressure ''inside'' of us is the same as the pressure outside, so there's no net force acting on us. If I'm not mistaken, what kills you is the high amount of oxygen in your bloodstream. Likewise, if you put an unopened bottle of Pepsi at the bottom of the ocean, very little will happen to it, because Pepsi, being a liquid, is pretty much incompressible. The only thing that will happen is that the air bubble at the top will shrink.
** Back when people lacked oxygen tanks and were breathing through an air line attached to the boat above, there were stories of sudden depressurization caused by the air line being cut causing the unfortunate diver to be [[BodyHorror squeezed into his/her helmet]] by the surrounding water pressure. Old time diving suits did have safety valves that were supposed to trip to prevent this, but they often weren't maintained and could rust open, preventing them from working.
* Among the victims of the persecution and martyrdom of {{Japanese Christian}}s in XVII century Japan, [[http://en.wikipedia.org/wiki/Martyrs_of_Japan#Petrus_Kibe_Kasui_and_187_Companion_Martyrs_of_Japan the Martyrs of Unzen]] were either forcibly drowned in the Shimabara river or, as depicted in {{Amakusa 1637}}, fatally scalded in the sulphur springs of Unzen.\\
More than one myth about Roman martyrs mentions them being tied to stones or anchors and then tossed into either the sea or rivers. [[ArtisticLicenseHistory Some of them are, however, very inaccurate]]: since the Romans were very pragmatic people, martyrs would have '''NEVER''' been thrown in rivers because their corpses would contaminate them (unless it was a public lynching instigated by mobs, instead of an actual and legally-sponsored execution), and if the anchors were tied to their necks, the weight and size would've caused them to ''[[OffWithHisHead rip the victim's head off]]'' instead of pulling them down to the river's bottom. (Besides, why waste huge and probably very necessary anchors anyway?)\\
In TheFifties, [[http://en.wikipedia.org/wiki/J%C3%A1nos_Scheffler Blessed János Scheffler]] was murdered by the Romanian communist regime via being scalded to death after his refusal to join a national Church under the thumb of the regime.
* Taken literally with anyone who has [[http://en.wikipedia.org/wiki/Aquagenic_urticaria Aquagenic urticaria]], an extremely rare form of allergy where contact with water causes skin to break out in painful hives and welts. While taking showers, jumping in pools, and walking in the rain are a big no-no, some cases are so severe that those suffering the condition can't even drink, sweat, cry or even give birth without getting a painful reaction.
* Obviously, very effective to kill a fire. It does not work with all types of fire, though, relying largely on the combustible that fuels it - adding water to a grease fire will just create a fireball (as the water instantly boils into steam and sprays the oil into a fine mist), and burning magnesium can split water apart into hydrogen and oxygen (which are both highly flammable).
* A [[https://en.wikipedia.org/wiki/Water_jet_cutter Water jet cutter]] (think of a pressure washer on steroids) can cut through plastic and wood with ease. Combined with an abrasive agent it can cut through ''steel''. Naturally one of these can cut through flesh just as easily if mishandled...