Why Are 96,000,000 Black Balls on This Reservoir?

I took a boat through 96 million black plastic balls on the Los Angeles reservoir to find out why they're there. The first time I heard about shade balls the claim was they reduce evaporation. But it turns out this isn't the reason they were introduced.
Huge thanks to LADWP for arranging this special tour for me. Next time let's put the GoPro on the submersible!
The balls are made of high density polyethylene (HDPE) which is less dense than water so they float on the surface of the reservoir even if they break apart. They are 10cm (4 inches) in diameter and contain about 210ml of water. So the main reason they are on the reservoir is to block sunlight from entering the water and triggering a chemical reaction that turns harmless bromide into carcinogenic bromate. This effect occurs with prolonged exposure to bromate so regulators insist that levels be kept below 10 microgram per liter on average over a 12 month period.
Special thanks to Patreon supporters:
Donal Botkin, Michael Krugman, Ron Neal, Stan Presolski, Terrance Shepherd, Penward Rhyme and everyone who provided feedback on an early draft of this video.
Thanks to:
Las Virgenes Reservoir for footage of initial shade ball dump
Euro-Matic for bird into jet-engine footage
Researched and Produced by Casey Rentz
Animations by Maria Raykova
Music from epidemicsound.com "Colorful Animation 4" "Seaweed"
And from Kevin MacLeod "Marty Gots a Plan"
This is an educational video about the science of water quality.



  • This can’t be healthy where is the sun sun can’t even get to that water is it gonna be full of bacteria there’s a reason that we don’t have balls over the top of water this is a really bad mistake and I think they’re going to find out that this is going to be deadly for a bacteria and stuff that you can even describe. And you won’t even know what kind of bacteria is created because I’ll be so different from anything we’ve ever seen. This is absolutely absurd and taxpayers of paid for this

    Misorganic1Misorganic1Před 2 minutami
  • Thanks for putting a gas powered engine through my drinking water lol

    Edward BakerEdward BakerPřed 5 minutami
  • Because that reservoir is MAJOR slut.

    opugilistopugilistPřed 21 minutou
  • Wow, the answer was more boring than I anticipated!

    SteveStevePřed 24 minutami
  • Because 48 million black babies didn't need them any longer. Go abortions.

    Joe DukeJoe DukePřed 27 minutami

    Dean FenderDean FenderPřed 27 minutami
  • Be proud of this idea -.-. In a world were we are trying to get rid of plastic, plastic is never a good solution, especially 6 million plastic balls.

    Alex BorrAlex BorrPřed 34 minutami
  • My Guess before the video is they're there for some sort of temperature control situation

    Tru421Tru421Před 35 minutami
  • Someone could dump a body in there and it will never be found.

    jeremiah christejeremiah christePřed 42 minutami

    Jon HeimsjøJon HeimsjøPřed 49 minutami
  • $3b in balls.

    ElijahMFearonElijahMFearonPřed hodinou
  • Another reason why i don't want to move to California is because of the traffic and the liberals the liberals and the state is a mess I would love to move to Texas Texas is much better

    dragonball slayer326dragonball slayer326Před hodinou
  • 5:51 a bird flies into the jet :()

    Dave HoinkaDave HoinkaPřed hodinou
  • Great video

    dragonball slayer326dragonball slayer326Před hodinou
  • *To the people who wants the answers quick instead of scrolling down thousands of pointless comments. They are doing this to cut down costs of reducing the algae problems since they were spending a lot of money on chlorine. Also, a myth debunked joke. Veritasium: it's rare to see 96,000,000 of anything. AutspieDrough: Well there's sand, cells, dirt, grass, dust, atoms, molecules, and a lot more so it's not rare at all.*

    AutspieDroughAutspieDroughPřed hodinou
  • Another reason LA is such a strange place

    drakg002drakg002Před hodinou
  • Is this BPA plastic balls, well its probably to make LA people more gay

    frankwhite83ablefrankwhite83ablePřed hodinou
  • Your mother has seen more black balls than that!

    Austistic AristotleAustistic AristotlePřed hodinou
  • I'm so confused what does he mean "why" there's legit a video of him putting them inside

    Lola Is My BitchLola Is My BitchPřed hodinou
  • Aren't those balls to reduce evaporation?

    The Devil's AdvocateThe Devil's AdvocatePřed hodinou
  • "the money we save on chemicals and evaporation will pay for half of the balls"...so you're not saving money...tax payers are now paying 50% more.

    NebulousNebulousPřed hodinou
  • I admit, I only clicked to get this out of my recommendations. But I stayed and watched because I've been subbed to Veritasium for a while and generally like his videos. Now I hope CH-visions will realise I caved in to their annoying insistence and get that thumbnail out of my face!

    NightwolfNightwolfPřed hodinou
  • balls are black for a reason, looked at my nuts* Me: no wonder why its black..

    I do those cumbo to cumbackI do those cumbo to cumbackPřed hodinou
  • 4:16 chlorine is safe to drink?

    Toxic RizeToxic RizePřed hodinou
  • 96 million miles to the Sun!

    Barry WhiteBarry WhitePřed hodinou
  • looks like poison

    Simone RaymondSimone RaymondPřed hodinou
  • For those who don't care for the filler: 3:01 Original purpose of the balls: 5:37

    qwigy hurpusqwigy hurpusPřed hodinou
  • Would be cool if white worked and it would help with reflecting sunlight and reducing warming somewhat

    jonashajonashaPřed hodinou
  • Does not this affect the Environmental system? The birds are not coming to the lake anymore

    ghalia mughalia muPřed hodinou
  • That was interesting. However, is running a outboard engine where the exhaust exits the engine under water a good idea...YUCK!

    AV8TORAV8TORPřed hodinou
  • So...bromide + chlorine + sunlight mixed in H20 equals LIBERALISM ?? These BLACK balls are a cure for California's Liberalism ! 🤗🤗🤗

    Rocky ORocky OPřed 2 hodinami
  • Veritasium: It's very rare to see 96 million of something Me: *P E W D I E P I E*

    iciclearmsiciclearmsPřed 2 hodinami
  • To stop birds and wildlife sitting on the water. Stop algee growth and stop evaporation. ..

    Ben ParBen ParPřed 2 hodinami
  • Rack em up!

    Greg LecuyerGreg LecuyerPřed 2 hodinami
  • How did i get here? Literally 3am

    Sebastian KristiansenSebastian KristiansenPřed 2 hodinami
  • For some reason I thought I saw this a couple years ago... weird.

    That Guy MUFFINThat Guy MUFFINPřed 2 hodinami
  • If someone fell into it, what would happen.?

    M. MuradM. MuradPřed 2 hodinami
  • Excellent video with Spanish subs!

    kopec82kopec82Před 2 hodinami
  • *World's Most Reservoir Reservoir Loses 96 Million Balls in a Matter of Days - New CH-visions Record!! (NOT CLICKBAIT!)*

    Dooby McFoosenDooby McFoosenPřed 2 hodinami
  • How did no one notice the death of that bird at 5:52 ?

    DGMDGMPřed 2 hodinami
  • So 48,000,000 black men are now eunuchs?

    Justa FoolJusta FoolPřed 2 hodinami
  • to save you the work of watching it ….in reservoirs black balls are used to stop sunlight converting bromide into poisonous bromates and @5.51 after listening 20 times he said, 'to keep the wild foul off so they didn't get into jet engines' so if you failed to catch that there you are

    DeShawnDeShawnPřed 2 hodinami
  • When you have trypophobia, but you're too curious.

    Candy WangCandy WangPřed 2 hodinami
  • Rip random bird that got blended at 5:50

    Ok.Ok.Před 2 hodinami
  • Wish I was the sales rep that got paid the commission on $32M of black balls! That guy must literally be balling now!

    LotusLamboLotusLamboPřed 2 hodinami
  • Hey” has anyone seen my black ball ...🙇‍♂️

    Truth 7Truth 7Před 2 hodinami
  • I would think sooner or later the balls would lose their UV protection and would break up.Yes or No?

    Steve's Outdoor WorldSteve's Outdoor WorldPřed 2 hodinami
  • Why oh WHYYYYY did you never even TOUCH them!! Like put your got damn hand down in that ball soup and swirl like a MAD MAN!!🤪 Especially when the boat is moving!!😛 And what if the boats propeller shreds a few.. must've happened right!? And doesn't that engine pollute the water?? I mean, it wasn't an electric one was it? Ps. Bro-mate.. Wooooord!!

    Super knullischSuper knullischPřed 3 hodinami
  • The marvels of engineering!

    mgrn63mgrn63Před 3 hodinami
  • There are so many jokes to be made here that the only REAL option is just to make a joke about how many jokes can be made here.

    Steve McGeeSteve McGeePřed 3 hodinami

    Gags GAGSGags GAGSPřed 3 hodinami
  • Black is always right..

    sunday brileysunday brileyPřed 3 hodinami
  • I never knew there were 96 million balls in Los Angeles on anything... 😀

    Laura DeeLaura DeePřed 3 hodinami
  • Sippin on straight Chlorine

    Emin AtajanovEmin AtajanovPřed 3 hodinami

    Billie TyreeBillie TyreePřed 3 hodinami
  • A Gas outboard engine on the reservoir. Why not an Electric boat that wouldn't pollute the water.

    alenuikuaualenuikuauPřed 3 hodinami
  • talk about being blackballed 😮

    Mak MakMak MakPřed 3 hodinami
  • its really rare to have 96 million views

    Ilya KamenshchikovIlya KamenshchikovPřed 3 hodinami
  • Derek: it's very rare to see 96 million of anything Pewds: yeah? Look at my subscribers, I'm almost there.

    Utkarsh MishraUtkarsh MishraPřed 3 hodinami
  • In Seattle we have many open water reservoirs and I'm sure the same problem exists with carcinogens but of course no one is even talking about the issue or trying to solve it. The politicians are all too busy trying to figure out how to collect more taxes to spend on their pet projects.

    Mike BrelerMike BrelerPřed 4 hodinami
  • I feel like I could run across the surface of the black balls if I run fast enough

    Andrew LeximaAndrew LeximaPřed 4 hodinami
  • In Seattle Washington we have many open water resivuors

    Mike BrelerMike BrelerPřed 4 hodinami

    Waheed HassanWaheed HassanPřed 4 hodinami
  • Bromide is not harmless. One of the three BAD halogens. Effects the thyroid. Chlorine also a bad halogen, the other being fluoride. Think about it.

    Dennis MurphyDennis MurphyPřed 4 hodinami
  • To keep water from evaporating.

    The BlissThe BlissPřed 4 hodinami
  • If not for the durability carbon black provides, the balls would be more efficient if they were white right?

    Diogo CabanasDiogo CabanasPřed 4 hodinami
  • 5:50 R.I.P speckled bird @ least yo u got 30M views (MAYBE)

  • Veritasium: it's really rare to see 96 million of anything Pewdiepie fans: Am I a joke to you

    RadWaffle WafflearmyRadWaffle WafflearmyPřed 4 hodinami
  • Is it safe for a motor boat to roam around in the reservoir?

    Claudia De FalcoClaudia De FalcoPřed 4 hodinami
  • Who else is here from the "my video went viral" video to watch the viral video lol?

    Torri HixonTorri HixonPřed 4 hodinami
  • The SHADE balls are black to keep light out of the water Wow Congrats A new fact

    SunsetColorsSunsetColorsPřed 4 hodinami
  • LA sux!!!!!

    KingBadMasterCoryKingBadMasterCoryPřed 4 hodinami
  • this is gay

    J-Money GDKJ-Money GDKPřed 4 hodinami
  • Good thing not "Blue Balls," but that's another video! 💃😁🤣

    Coiled SteelCoiled SteelPřed 4 hodinami
  • Se ve bien kulero eso en el agua!!

    MI CRMI CRPřed 4 hodinami
  • unreal ~ now what happens when the water now gets heated ~ heating the bromate and chlorine and what about the release of the chemicals they are used to make them~ nano in the water--carbon black ~ WTF !!!!! this is going to release into the water and cause environmental \~ what this guy is saying is totally BS ~ everyone better get a RO or distiller ~ the cancer rates and the auto immune is going to spike Tony

    HerbsPlusBeadWorksHerbsPlusBeadWorksPřed 4 hodinami
  • The black balls are there to keep the water from evaporating

    Justin LoehmerJustin LoehmerPřed 4 hodinami
  • Cool!

    Gargoyle McCoyleGargoyle McCoylePřed 4 hodinami
  • So they were worried about carcinogens, so they put a bunch of plastic balls in the water........🤔😑

    jleettriple7jleettriple7Před 4 hodinami
  • “Did you think they were nuts” 🤣🤣🤣

    Daniel SchrockDaniel SchrockPřed 4 hodinami
  • Is that billy Joel working undercover driving that boat!lol

    John NealJohn NealPřed 4 hodinami
  • LOL.

  • I was going over the Grapevine a couple of months ago and I saw the reservoir and was completely baffled by what was floating on top of it. Now I know. Great post.

  • So water goes from filtering to laying in open air before getting to the peoples house.. I can see nothing wrong??

    Alexandre LoensAlexandre LoensPřed 5 hodinami
  • Did you see that? That airplane engine suctioned a bird. ☹️

    bbgirlivanvanessabbgirlivanvanessaPřed 5 hodinami
    • Minute 5:50-5:52

      bbgirlivanvanessabbgirlivanvanessaPřed 5 hodinami
  • Okay, so why didnt he get into how unsafe it must be to fall in!!

    SparkyrootsSparkyrootsPřed 5 hodinami
  • Why is there a motor boat in drinking water

    Wayne's hermanWayne's hermanPřed 5 hodinami
  • Yes more plastic chemicals im the drinking water, fumny thought the sunlight sterilises.. would prefer the algae.

    Alice JacksonAlice JacksonPřed 5 hodinami
  • Worried about the balls leaching, but driving through the reservoir with a 4 stroke gas motor?!Too funny! At least the balls cover up anyone seeing the oil spilling out of the engine 😂

    Jesse MockJesse MockPřed 5 hodinami
  • Before long it will be 96 million tons of my blue balls on that Resevoir

    FrontendFrontendPřed 5 hodinami
  • I dunno call me old fashion but I dont want anyone putting anything in my drinking water, fluoride and black balls including

    Goog GooGoog GooPřed 5 hodinami

    PAS3 TH3RiCH3ZPAS3 TH3RiCH3ZPřed 5 hodinami
  • Morron

    Phong LePhong LePřed 5 hodinami
  • How does the black carbon die help reduce the breakdown of the plastic via solar energy? Does it strengthen the bonds in the plastic?

    Michael PhillipsMichael PhillipsPřed 5 hodinami
    • Nope, its kinda like melanin in human skin. It absorbs the light, e.g. it transforms light photons into heat energy in safe manner, instead of letting photons hit chemical bonds in polymer structure that can break them down, similar to how melanin absorbs UV light so it doesnt penetrate deep into skin and cause sunburn/skin cancer.

      Mad manMad manPřed 5 hodinami
  • bruhmide and bruhmate

    Flaprise 1337Flaprise 1337Před 5 hodinami

  • Plastic in the hot sun leaching into the water supply. Yum.

    Lois DegeneffeLois DegeneffePřed 6 hodinami
  • omg the bird that dies at 5:50 in the turbine

    TorohiTorohiPřed 6 hodinami
  • Once again the private sector was ahead of Government but the big question is why treat the water and then store it in a open pond. Why not treat it and pump it to the consumer like the rest of the world.

    Kurt SmithKurt SmithPřed 6 hodinami
  • why just not just chlorine? WTF its ur drinking water. Your body is not a swimming pool. Your important bacteria will die in your body which normally helps you

    HaloheldHaloheldPřed 6 hodinami
Why Are 96,000,000 Black Balls on This Reservoir?