->'''Construction Worker''': That nutjob Sweet Tooth is gonna poison the water supply!\\
'''Pizza Girl''': This is even worse than when The Joker poisoned the water supply!\\
'''Construction Worker''': Or when Scarecrow poisoned the water supply!\\
'''Pizza Girl''': Or when Killer Croc poisoned the water supply! That's how he died, the poor fool.
-->-- ''Theatre/HolyMusicalBatman''

Fear of drinking water is a classic paranoia, especially since in medieval times or earlier it could be quite difficult to come by a clean water supply (just imagine what it was like it the days before water filtration and the only river within miles had thousands of people throwing all their waste, including biological wastes, into it upstream) and thus a well could be the center of life for miles around. If anything happened to it or anyone tried to contaminate it, you'd never know until it was too late...

As such, [[SuperVillain super-villains]] or [[GovernmentConspiracy government conspiracies]] putting horrible stuff in the water has been the fodder of fictional plots for years. In other settings, [[WindmillPolitical the paranoia is not justified but might still be relevant to the plot]]. In stories set in modern, developed countries, this trope often employs some ArtisticLicense. The sheer quantity of fluid in most water infrastructures would dilute most added contaminants to virtually nothing, not to mention the various micro-organisms that would absorb the initial damage in many cases, or the security measures water facility equipment has to prevent exactly this kind of tampering. Realistically, achieving this intentionally would require [[AwesomeButImpractical jumping a lot of logistical hurdles]] (unless one believes in [[ArtisticLicensePharmacology homeopathy]], at any rate).

Compare TamperingWithFoodAndDrink, which is at least normally intended as a (deadly) prank. Can be a PoisonAndCureGambit.


[[folder:Anime and Manga]]
* In ''Manga/BirdyTheMighty'', this was Seichiro Hikawa's plan for the people of Tokyo, to turn them into "retro soldiers" by tainting the city's water supply with serum. See here, [[http://www.youtube.com/watch?v=kxFqMG_OSNs starting at 4:27]].
* ''Anime/NinjaScroll''. A village well is poisoned to make it appear a plague is sweeping through the area -- everyone flees leaving the bad guys free to carry out their plans without witnesses.
* In ''Manga/RurouniKenshin'', Hannya forces Megumi to come with him by threatening to pour a vial of mercury into Kamiya Dojo's well.
* In ''Manga/SnowWhiteWithTheRedHair'', Shidan manages to do this unintentionally by secretly raising beautiful glowing flowers in a cave that housed a spring in Lyrias. The flowers cause the water to become poisonous.

* A frequent plot of ComicBook/TheJoker is to slip Joker venom into Gotham's water supply.
** {{Deconstructed}} in one ''{{Franchise/Batman}}'' comic, where Bruce deduces Narcosis, the VillainOfTheWeek, ''won't'' put his hallucinogen into the water supply, because it's too easy to shut off. Instead, he plots to put it in the ''milk'' supply.
** ''ComicBook/SupremePower'' (an AlternateCompanyEquivalent to the DCU and especially the Justice League) was all too happy to show how terrifying this would be in the spinoff where Nighthawk (the Franchise/{{Batman}} analogue) deals with an OmnicidalManiac who has developed an always lethal poison and is trying to kill off a major city with it. It gets {{Deconstructed}} when Nighthawk points out to the man that the water reclamation plant doesn't connect directly to the reservoir and there are safeguards in place to shut it off automatically if it's contaminated.
* Often used as a plot point in the adventures of [[ComicBook/{{Blueberry}} Lieutenant Blueberry]]: one or more characters finally come across a water source after a long trip through the desert... only to find out that the bad guys (or at any rate, someone who does not want to see them come out of the desert alive) have poisoned it by throwing in a dead animal, usually a horse.
* A ComicBook/CaptainAmerica arc, during Cap's "The Captain" phase, had Madam Hydra/Viper putting drugs into Washington D.C.'s water supply. What did said drugs do? Turned everyone who drank the water into half-human, half-snake hybrids.
* During the ''Apocalypse War'' arc prologue of ''ComicBook/JudgeDredd'', ''Block Mania'', Orlok introduces the Block Mania to the city via the water supply.
* The Moon Kings, a criminal gang fought by the title character in volume one of ''Comicbook/MoonKnight'', plan to extort Chicago by contaminating its water tables with a psychotic/hallucinatory drug. It's noted in-story that Chicagoans actually like and trust their water supply, unlike New Yorkers.

* In ''FanFic/ACureForLove'' [[spoiler: [[AGodAmI Kira]]]]'s ultimate scheme is to release a SterilityPlague into the water supply so that he may gain absolute control over the human race.
* In the past of ''FanFic/TouhouIbunshu'', [[spoiler:Yukari]] killed Yuyuko's parents by tossing a dead fairy in the waterhole.

[[folder:Film -- Animated]]
* In ''WesternAnimation/ToyStory'', one of Woody's quotes that play when someone pulls his string is "Somebody's poisoned the waterhole!"
* In ''[[Film/{{ET}} San T]] OldMasterQ'', the EvilPlan of the antagonists begins with the mooks adding laxatives in the various water sources in Mr. Chiu's theme park.

[[folder:Film -- Live-Action]]
* In ''Film/ErinBrockovich'', PG&E tries to cover up the fact that they were poisoning the groundwater of the town Hinkley, California with Hexavalent Chromium, which resulted in most of the town suffering from illness and cancer.
* The plot of the old action flick ''Never Too Young To Die'' involves the hero trying to stop a bad guy played by Gene Simmons from poisoning the water supply.
* ''Film/DrStrangelove's'' [[GeneralRipper General Jack D. Ripper]] had a paranoid belief that there is a Communist conspiracy involving water fluoridation which will lead to contamination of everyone's "precious bodily fluids."
* In ''Film/TheTuxedo'', Dietrich Banning (Ritchie Coster) is the owner of a bottled water company. By infecting a swarm of water strider insects with a strain of bacteria that causes water to dehydrate rather than rehydrate the drinker and letting them loose, he plans to render all the water in the world undrinkable except his own, thus increasing its value.
** Although you'd figure that just people would just boil the water, which is a very common method of purification that is extremely reliable.
* ''Film/BatmanBegins'' had a variation. Scarecrow laced Gotham's water supply with his fear toxin for months, without anyone realizing it. The toxin had no effect in this form. [[spoiler:It needed to be absorbed through the lungs to have an effect -- the bad guys' ultimate plan was to use a microwave emitter to vaporize Gotham's water supply, thereby exposing the whole city.]]
* ''Film/{{Signs}}'': Bo, the little girl, would start glasses of water then find something wrong with them (such as "It has [her brother's] amoebas in it!") and stop drinking them, leaving them scattered all over the house, half-full. [[spoiler: It turned out leaving the glasses all over was Bo being precognitive but unwilling or unable to explain it. Water was harmful to the hostile aliens, one of which had gotten into the house, and when they needed to be able to hurt it, it found itself standing in a room surrounded by partially full water glasses]].
* The Norsefire party was implied to have done this in the movie version of ''Film/VForVendetta''.
* [[UsefulNotes/SovietInvasionOfAfghanistan the Soviet tank crew]] in ''Film/TheBeastOfWar'' is shown emptying poison canisters into a well while attacking a village. Later on one of the mujahadeen is killed when he drinks from a poisoned well.
** The Soviets' poisoning of every water source they come across ends up biting them in the butt later, as a Soviet helicopter crew unknowingly drinks from a pond the tank crew had poured cyanide into earlier and all die - before they can radio assistance for the stranded tank.
* An inverted version is mentioned in ''Film/{{Contagion}}''. The US government wants to know if they can distribute the cure this way, but is told that it would only dilute it beyond practical effectiveness.
* In ''Film/TheCrazies2010'', the culprit turns out to be a bio-weapon aboard a plane that crashed into the marshes near the town, which are used for drinking and watering crops. When the protagonist finds out about this, he demands that the mayor shut down the water supply, only for the mayor to refuse, claiming that is would devastate the town (given that it's planting season).
* Halfway through ''Film/WildBeasts'', it is discovered that the animals are acting crazy because there is PCP in city's water supply.
* In ''Film/RurouniKenshin'', Kanryu's men flush Megumi out of hiding by pouring rat poison into the village well. She is able to treat everybody who drank the tainted water, but she decides to stop hiding and return to Kanryu's mansion, fearing more attacks on the people.
* In ''Film/TheMenWhoStareAtGoats'', Bill puts LSD in the water supply of a military camp sending the whole camp on a trip.
* In "The Challenge" (1970 TV movie) a CombatByChampion takes place on a Pacific island. The US combatant poisons all the water sources on the island except one in the hope of ambushing his opponent there.

* ''Tribesmen of Literature/{{Gor}}'' FantasyCounterpartCulture to arabs/desert dwellers; an outside party causes unrest by masquerading as one of two opposing tribes and attacking the others' oases. At one point they destroy a well, which tells Tarl's best friend of the book that they aren't really tribesmen because no tribesman, no matter how evil, would destroy a well.
* Donald J. Sobol's ''Literature/SecretAgentsFour''. A criminal organization named Cobra plans to put a drug in the city of Miami's water supply. The drug causes the victim to relive the last 24 hours, rendering them helpless.
* "When the Past Went Away" by Creator/RobertSilverberg: Amnesia-inducing drugs are dumped in a city's water supply, leaving everybody in the city with no memory of who they are.
* Defied by Alastor Moody in his first appearance in ''Literature/HarryPotterAndTheGobletOfFire'': The known paranoid drinks only from his canteen, but [[spoiler:it's a subversion as this conveniently allows an impostor to impersonate Moody by taking regular sips of Polyjuice Potion]].
* In ''The First Virtue'', part of ''Literature/StarTrekStargazer'', a fanatical Cordracite poisons her city's water supply in order to escalate a conflict with another race, assuming they'll be blamed.
* In ''Discworld/{{Jingo}}'', there was a man who had poisoned the only well for twenty miles worth of desert, killing five men, seven women, thirteen children, and thirty-one camels (some of them being very valuable camels). [[spoiler:This is the source of 71-Hour Ahmed's name. Once he had solid evidence and witness testimony, he executed the poisoner before the customary three days of SacredHospitality was up]].
* In a ''Literature/PreludeToDune'' prequel novel, a group of Harkonnen soldiers manage to capture a young sandworm. Just for fun, they drown it in a hidden water tank near a Fremen village as punishment for hoarding water, knowing that pure Water of Life (the result of an infant worm regurgitating water, poisonous to it) is pure poison. When Liet Kynes later finds the village, most of the villagers are dead, while the rest are delirious and close to death. He puts them out of their misery and then slaughters a whole bunch of Harkonnens.
* Done ''twice'', for different reasons, in Creator/StephenFry's novel ''Literature/MakingHistory''. The first time, they put a water-soluble contraceptive in the well near the house where Adolf Hitler was born, thus preventing his birth. [[spoiler:The second time, they put a dead rat in the same well, to prevent people from drinking it, because [[HitlersTimeTravelExemptionAct the world without Hitler turned out to be even worse.]]]]
* In ''Literature/{{Goldfinger}}'', part of the EvilPlan to loot Fort Knox involves killing everyone in the area by poisoning the local town's water supply.
* In the Literature/DirkPittAdventures book ''Sahara'', the plot-driving ecological disaster is caused by the CorruptCorporateExecutive's improper disposal of nuclear waste that subsequently leaked into the water supply. At the end of the film, [[spoiler:he gets subjected to LaserGuidedKarma - Dirk and Al have him tied down out in the open sun until he sunburns, then trick him into drinking that polluted water. He dies a raving loon.]]
* ''Literature/WetDesertTrackingDownATerroristOnTheColoradoRiver'': When the bomber realizes that the All-American Canal is too heavily guarded for another bombing, he forces its shutdown with a bogus threat of having poisoned the water.
* In ''[[Creator/JohnGrisham The Appeal]],'' this is the basis of the lawsuit that drives the plot.
* In ''Literature/TheWishsongOfShannara'', the Mord Wraiths poison Heaven's Well, the source of the Silver River, and the entire Four Lands sickens as a result.

[[folder:Live-Action TV]]
* On the ''Series/{{Brimstone}}'' episode "Carrier", Stone has to stop a PoisonousPerson before she can throw up in the local reservoir.
* ''Series/DoctorWho'':
** In [[Recap/DoctorWhoS1E7TheSensorites The Sensorites]], the eponymous species are being affected by a disease that the good guys later trace to [[HumansAreTheRealMonsters a human expedition poisoning their water supply]].
** There's also the special [[Recap/DoctorWhoS30E16TheWatersOfMars "The Waters of Mars"]], in which the aliens are ''in'' the water, and use it to infect their victims.
* In the ''Series/{{Highlander}}: The Series'' multi-parter about the HorsemenOfTheApocalypse, the BigBad planned to contaminate water supplies with a bioweapon, ForTheEvulz.
* In ''Series/PowerRangersZeo'', the Machine Empire tried to contaminate all the Earth's water in order to kill off humanity while at the same time turning it into something they could swim in.
* Played with in an episode of ''Series/StarTrekTheNextGeneration'' where Data - who has amnesia and doesn't know about his own history or Starfleet - is accused of poisoning a well in the village he's living in, but he's really trying to cure them of radiation poisoning by putting the cure in the drinking water (resorting to subterfuge because the villagers don't trust him enough to take his cure if he offered it openly).
** Another episode has the VillainOfTheWeek do this as part of a PoisonAndCureGambit - which itself is a cover [[XanatosGambit for his real goal to get his hands on Data]], so he can add a Soong-type android to his collection of rare items..
* ''Series/TheTwilightZone1959'' episode "Black Leather Jackets". A group of aliens is sent to Earth to KillAllHumans by contaminating city water reservoirs with deadly bacteria. They are in the form of teenage human males wearing the eponymous apparel.
* In ''Series/TheXFiles'' episode "Anasazi", the shadowy organization puts LSD into Mulder's water supply, causing erratic behavior that discredits both him and the case he is currently following. And since it wasn't just Mulder's water supply, but his entire apartment building's, it also caused at least one murder there.
* In ''Series/{{Merlin}}'', Nimueh conjured up an Afanc and deposited it into Camelon's water supply.
* An episode of ''Series/NUMB3RS'' involves a terrorist plot to put sarin gas into the Los Angeles water main. Not only would this kill anyone drinking the water but also anyone taking a shower, doing the dishes, or being in the vicinity of sprinklers.
* In ''Series/{{Batman}}'', The Joker turns the Gotham City water reservoir into strawberry jelly (That tastes like axle grease). As the Dynamic Duo works to undo this, Batman notes to Robin that the situation is affecting more than just the drinking water supply, if there was a fire while the water is in that state, the Fire Department would not be able to put it out.
* The first episode of ''Series/TheProfessionals'' ("Private Madness Public Danger") had a chemical expert threatening to contaminate London's water sources with a concentrated hallucinogenic drug unless his political demands were met. He starts with a few drops in the coffee dispenser of a chemical company, a hypodermic in a beer keg at a pub, and plans to disperse a gallon of ADX in a city reservoir.
* In the [[ShowWithinAShow "Lethal Weapon 5"]] episode of ''Series/ItsAlwaysSunnyInPhiladelphia'', [[UnsympatheticComedyProtagonist Dennis and Mac]] star as [[Film/LethalWeapon Murtagh and Riggs]] investigating a Native American casino's involvement in "tainted tap water".
* In season two of ''Series/TheShannaraChronicles'', this turns out to be the Warlock Lord's plan; putting his blood in Heaven's Well, and thereby the Silver Lake and from there the whole water table of the Four Lands, turning everyone who drinks it into zombies under his control.

[[folder:Tabletop Games]]
* The ''TabletopGame/{{Illuminati}}'' card-game and ''TabletopGame/{{GURPS}}'' module has the "Fiendish Flouridators" as one of it's many conspiracies.
* ''TabletopGame/{{Paranoia}}'' supplement ''Acute Paranoia'', adventure "Outland-ISH". The high Programmer of ISH sector is putting a drug called ZAP! in the water supply for Infrared citizens. It tremendously increases productivity but eventually kills the drinker.
* ''TabletopGame/MagicTheGathering'' has [[http://magiccards.info/shm/en/193.html Poison the Well]] and [[http://magiccards.info/in/en/126.html Tainted Well]], which can mess with your opponent's lands.
* One short adventure for ''TabletopGame/{{Ravenloft}}'' involved [[spoiler: a pair of devils]] that were poisoning a town's water supply with a toxin that induced hallucinations.

* Poisoning a city's water supply was a potential espionage action in ''VideoGame/{{Civilization}} II''. Succeeding reduced the city's population.
** You can do the same in ''Civilization IV'', although instead of reducing the population directly, the city takes a huge "unhealthiness" penalty...which might just reduce the population.
* ''VideoGame/DragonQuestVII'' has Krage/Grondal, whose sole source of water is a single well in the middle of town. Then it gets spiked with a poison that [[BrainwashedAndCrazy makes everyone believe that they're]] [[BigBad the Demon Lord/King]]. Considerable amounts of StupidEvil antics ensue until your merry band is able to do anything about it.
* Early on in ''VideoGame/FinalFantasyVI'', Kefka does this to the village of Doma in one of the definitive crossings of the MoralEventHorizon in console gaming.
* [[AllLovingHero Micaiah]] of ''[[VideoGame/FireEmblemTellius Fire Emblem: Radiant Dawn]]'' rejects this as a tactic to take out a well defended enemy base when it's suggested. Rather than point out the questionable ethics involved, she explains that people would ''see'' it as a questionable act, and start to question their motives, maybe turn against them.
* A man in the first level of ''VideoGame/HalfLife2'' tells you not to drink the bottled water in City 17 because "they put something in it to make you forget".
* Enclave President John Henry Eden in ''VideoGame/{{Fallout 3}}'' attempts to convince the player to insert a container of novel Forced Evolutionary Virus into the water supply at Project Purity in an effort to achieve the Enclave's goal of killing everyone in the Capital Wasteland with the slightest degree of mutation. He says that the player character, having been born in a vault, is probably immune to the disease. [[spoiler:He's wrong.]]
* One of the potential side quests in the first ''VideoGame/{{Diablo}}'' game involves Tristram's water supply being poisoned. When you go into the catacombs and find the spring, killing the monsters around it will turn it back to normal.
* In ''VideoGame/TheSimsMedieval'', Spies and Wizards can put potions in the well. Some of them are beneficial, but they can add something like Vomicious Venom, which makes people throw up, or a sleeping potion.
* One potential chain of events in ''VideoGame/TheYawhg'' involves a potion getting dumped into the water, leading to horrifying mutations. A seperate EventFlag deals with a leech infestation. These events can get triggered in the same game, resulting in mutant leeches.
* Just in case you thought you could get away with not taking your [[GovernmentDrugEnforcement Joy]] in [[VideoGame/WeHappyFew Wellington Wells]], the water supply appears to have been laced with the medication. And, of course, [[ResourcesManagementGameplay you have to take a drink sometime...]]
* In ''VideoGame/KultHereticKingdoms'', one of Alita's tasks is to go and stop some Taymurian shamans who are contaminating a river as part of their campaign against the army of Corwenth.
* In ''Videogame/BatmanArkhamAsylum'', Scarecrow threatens to flood the Gotham river with his toxins and Joker pollutes the water flow to flood it with Titan.
* A side quest in ''VideoGame/FinalFantasyXIV'' has someone suspect that a farmer's paddyfield is tainted with something due to the smell. You find out that a plant monster contaminated the water source, which was seeping into the fields and also likely contaminated the food being grown.

* ''Webcomic/{{Buttersafe}}'' [[http://buttersafe.com/2009/09/01/the-evil-plan/ plays this for laughs]].
* ''Webcomic/SaturdayMorningBreakfastCereal'' [[http://www.smbc-comics.com/index.php?db=comics&id=528 also has fun with this]].
* Mentioned in ''{{Webcomic/Drowtales}}'' [[http://www.drowtales.com/mainarchive.php?sid=5772 at the council gathering]] as an example of how the "Queen's Law" (unwritten rules of clan warfare) has broken down.

[[folder:Web Original]]
* In a ''WebVideo/DoctorHorriblesSingAlongBlog'' prequel comic, the Evil League of Evil takes advantage of the city's superheroes going on vacation to try and poison the city's water supply. [[spoiler:When {{Super Zero|es}} Johnny Snow thwarts them by freezing the entire water supply, [[YourApprovalFillsMeWithShame they decide that's actually good enough]] and head back to their HQ.]]
** And the song "My Eyes" has Dr. Horrible contemplating whether or not to do this. "Any dolt with half a brain/Can see that humankind has gone insane/To the point where I don't know if I'll upset the status quo/If I throw poison in the water main."
* ''WebVideo/HolyMusicalBatman'' uses this, with a small parody of its use in Batman comics. When Sweet Tooth announces his plan to poison the water supply, several people comment about the how it's worse than the last couple times a supervillain poisoned Gotham's water supply.

--> '''Construction Worker''': That nutjob Sweet Tooth is gonna poison the water supply!\\
'''Pizza Girl''': This is even worse than when The Joker poisoned the water supply!\\
'''Construction Worker''': Or when Scarecrow poisoned the water supply!\\
'''Pizza Girl''': Or when Killer Croc poisoned the water supply! That's how he died, the poor fool.

[[folder:Western Animation]]
* In ''WesternAnimation/DarkwingDuck'', "[[Recap/DarkwingDuckS1E34DryHard Dry Hard]]" The Liquidator started out as an unscrupulous bottled water magnate who was contaminating the competitor's water in order to corner the market. He fell in a vat of his own poison and became a [[MakingASplash liquid being who could control all water]].
* ''WesternAnimation/SpiderManAndHisAmazingFriends'': The Green Goblin had a plot to put goblin formula in New York City's water supply, goblinizing the whole population.
* ''WesternAnimation/SpongeBobSquarePants'': Ultimately averted when Bubble Buddy wreaks havoc on Bikini Bottom.
-->'''Tom''': He poisoned our water supply, burned our crops, and delivered a plague unto our houses!
-->'''Townspeople''': He '''''DID?!?'''''
-->'''Tom''': No, but are we gonna sit around and wait till he does?!?
* In ''WesternAnimation/TheSimpsons'', Homer says that Shelbyville vowed to spike Springfield's water supply in revenge for Springfield burning down their city hall, but "they don't have the guts." Three guesses what happens to Marge [[MushroomSamba next.]]
* ''WesternAnimation/MonsterAllergy'':
** In one episode, the Gorkas were planning to spike the city's water supply, turning anyone who drank from it into Andro-Gorkas. Zick was able to thwart their scheme by evaporating the tainted water.
** In another episode, this was a side effect of draining the fluids from the HealingVat [[DarkLordOnLifeSupport Magnacat had been in]] since his encounter with [[GhostPirate Bristlebeard the Pirate]].
* Heroic version used in ''WesternAnimation/{{Underdog}}'' where the titular hero dropped his super energy vitamin pills in all the world's water sources in order to give humanity the strength to fight back against the MoleMen after the villains stole all the food in the world.
* In ''WesternAnimation/ActionMan2000'', one of [[EvilutionaryBiologist Dr. X's]] plots involved distributing an [[HatePlague aggression-inducing formula]] as an energy drink. He later attempts to up the ante by dumping it in a reservoir.
* ''WesternAnimation/{{Grossology}}'' had a particularly disgusting example of this, with bonus points for being unintentional. The villainous Sloppy Joe had taken a trip to the water treatment plant where he was ''[[{{Squick}} swimming in the water after it had been through the purification process]]'' leading several citizens, including main character Abby who prides herself on her strong stomach, to puke their guts out.

[[folder:Real Life]]
* In Medieval Europe, one of the motivations for anti-Semitic violence was that Jews were accused of poisoning the wells used by Christians. This is the ultimate origin of the name of [[http://en.wikipedia.org/wiki/Poisoning_the_well that logical fallacy]].
** Tragically (and ironically), there were a number of anti-Semitic riots and lynchings in late 12th Century Britain which ended with Jewish corpses and pieces thereof being dumped down a well, poisoning it after their deaths (most notably after the Clifford's Tower Massacre in York of 1190 AD- and the well they were dumped in supplied one of the richer Christian parts of town...)
* In a campaign in Northern Africa during UsefulNotes/WorldWarII, the Germans were upset to find a particular branch of SaltTheEarth strategy: every oasis they came to had a sign in English stating that the oasis had been poisoned by the British army. When they complained that poisoning water constitutes a war crime, the British pointed out that there was absolutely nothing forbidding ''[[LoopholeAbuse putting up false signs]]''.
* And yes, [[ConspiracyTheorist Conspiracy Theorists]] have accused governments of pulling this since the beginnings of government. We're not going to list them all, because if we did, we'd be here until the Whigs controlled Congress again.
* British statesman Lord Chesterfield wrote in ''Literature/LettersToHisSon'': "I cannot omit, upon this occasion, telling you that the Eastern emperors at Constantinople (who, as Christians, were obliged at least to seem to favor these expeditions), seeing the immense numbers of the 'Croisez' [crusaders], and fearing that the Western Empire might have some mind to the Eastern Empire too, if it succeeded against the Infidels, as 'l'appetit vient en mangeant'; these Eastern emperors, very honestly, poisoned the waters where the 'Croisez' were to pass, and so destroyed infinite numbers of them." (letter 51)
** It is also undoubtedly true that the Muslims had ''plugged'' (not poisoned; they expected to retake the territory eventually) the wells while retreating back to Jerusalem during the [[UsefulNotes/TheCrusades First Crusade]]. By the time the Crusaders took Jerusalem, they had nearly gone mad with thirst.
* In Flint, Michigan, the water supply was changed from the Great Lake to the Flint River, notorious for filth. This caused many people to suffer from lead poisoning, and caused national outrage at Governor Rick Snyder.