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.




  • Woah!! I think i remember telling you sbout this like 6 years ago

    Avery KollatzAvery Kollatz9 hours ago
  • Why 96? Why not 100million?

    Mister IceCreamMister IceCream9 hours ago
  • Informative ​kalgudi.com​/

    Uday Bhaskar MandalojuUday Bhaskar Mandaloju9 hours ago
  • 'It's very rare to see 96 million of the exact same comment' Comment section: 'hold my soylent'

    Bobo AyameBobo Ayame9 hours ago
  • Their real purpose is to contaminate all available water with xeno-estrogens so that there is no escape from its poison

    Bobo AyameBobo Ayame9 hours ago
  • they just turned that reservoir a cesspool of carcinogens. nice work humans.

    cookytrixcookytrix9 hours ago
  • Kim Kardashian has also had 96 million black balls on her face...

    BrandonB311BrandonB31110 hours ago
  • RIP to that poor Bird that the engine killed at 5:52 🤭😥

    Amoy McdonaldAmoy Mcdonald10 hours ago
    • 😱😵😰😨😢

  • At 5:52 that bird got shredded by the plane🙁

    Naruto 23Naruto 2311 hours ago
  • Thats almost as many Black balls as have been on the Kardashian's

    Walter DelcidWalter Delcid11 hours ago
  • I thought it was mr beast idea lol

    Ibrahim AlfatihIbrahim Alfatih11 hours ago
  • 32 million dollars worth of shade balls. That seems like an insane amount to pay for some reservoir shade.

    20eddiec20eddiec11 hours ago
  • It's BroScience..

    Thomas DroughtThomas Drought11 hours ago
  • ok so... why isnt this on every single water source like ever now?

    COM DRIVECOM DRIVE12 hours ago
  • Why aren't they more a lighter color to create less heat?

    laserus3333laserus333312 hours ago
  • The number of this 👍 I get shows the number of shade ball in the water 👇👇

  • This is a targeted misinformation campaign. These are undigested boba pearls. The government does not want you to know that boba pearls never break down. Stop the violence. Stop boba.

    Social SketchSocial Sketch12 hours ago
  • ....Never seen a place with so many black balls. ....Other than the Kardashians' house.

    George EdwardsGeorge Edwards12 hours ago
  • That dirty filipina would think about boba lol

    Johnny DoggJohnny Dogg12 hours ago
  • 3:00 for explanation

    EltyoEltyo13 hours ago
  • that reservoir is racist

    Grand TicklerGrand Tickler13 hours ago
  • 6:00 used to deter birds thank me later

    YPYP13 hours ago
  • YT you happy now? God damnit. Will you stop when there are as many views as there are balls?

    ecsyntricecsyntric13 hours ago
  • 5:52 R.I.P Bird

  • Why are they black and not white?

    matthew painematthew paine13 hours ago
  • thats a banger.

    Jai Cilento NeedsMoreCoffeeʕ•ᴥ•ʔߛ ̋Jai Cilento NeedsMoreCoffeeʕ•ᴥ•ʔߛ ̋13 hours ago
  • This is how stupid americans do stuff.. Instead of planting trees all around the lake, they manufactured 96million virgin plastic balls to further worsen the plastic problem in future when these balls gonna start getting rot.

    kb Bkb B14 hours ago
  • so thats drinking water yet they run an outboard motor in it hmmm

    Ainokea89Ainokea8914 hours ago
  • "Its very hard to see 96million of anything" Pewdiepie Subscribers: "Are we a joke to you?"

    taylorfisdboss5200taylorfisdboss520014 hours ago
  • Because there are 48,000,000 white women there.

    GuinnessandPizzaGuinnessandPizza14 hours ago
  • 5:54 r.i.p bird

    Xmerk _jaXXmerk _jaX14 hours ago
  • what do you call a chemical's friend bromate

    cammiecookiescammiecookies14 hours ago
  • VERY WELL DONE, and it's good to see that you got as many views as some gun videos so keep at it !!

    Dan BonacumDan Bonacum15 hours ago
  • ......so why is there a fking motorboat driving through drinking water????????????

    albert bahoogadinalbert bahoogadin15 hours ago
  • Is this where I should hide the body?

    KashKidSelfiesKashKidSelfies15 hours ago
  • wondering if a skydivers chute didn't open if he could survive that over the 50ft deep spot, those balls might help break the concrete like stop water provides, balls have enough give they might settle the fall survivable?

    nineball26nineball2615 hours ago
  • Next video idea: Diving into a swimming pool full of shade balls

    Lets_Get_Faded 18Lets_Get_Faded 1815 hours ago
  • why are 96,000,000 black balls in this res? cuz white guys don't give em up so easily... BAAHHH!!!!!

    nineball26nineball2615 hours ago
  • stupid fuckers

    Jay 13Jay 1315 hours ago
  • How did they test safety for years when this project isn’t that old?

    swimgirl24swimgirl2416 hours ago
  • So much plastic. 😱

    swimgirl24swimgirl2416 hours ago
  • Why are they black? Do they even work? Will they be looking for reparations after using them in the lake? When not doing their intended job, are they selling drugs and abandoning their sons and daughters? Black balls were a bad choice based on history.

    sn00chsn00ch16 hours ago
  • when you order extra boba

    Jenl AngJenl Ang16 hours ago
  • Wait why the hell is this reservoir AFTER the filtering plant? How the heck would any of that water be anything close to drinkable sitting out in the open like that even with chlorine in it? Not to mention doesn't treating it with a bunch of chlorine and letting it sit out in the open completely defeat the purpose of doing ozone filtration?

    Jaqen H'GharJaqen H'Ghar16 hours ago
  • 1 black ball = one of pewdiepie sub

    ZonedOutFNZonedOutFN16 hours ago
  • To keep water from evaporating as fast.

    ChristianMGTOW JamesTRChristianMGTOW JamesTR16 hours ago
  • Oh that nigga dead 5:50

    Thegamingmaniac33Thegamingmaniac3316 hours ago
  • the plastic will turn the fish gay lol.

    John BJohn B17 hours ago
  • All of this is very interesting but why did you have to show footage of a bird getting murdered by an airplane turbine?

    heavymetalkitten13heavymetalkitten1317 hours ago
  • Note to Scientists and Blockchainers. (CARDANO, ETHEREUM ++) USE WHITE BALLS IN THE ARCTIC AND ANTARCTIC FOR REVERSAL OF THE ALBEDO EFFECT. xEXI.O FOUNDER PZP.IO Paul Z Peteranac. Black balls, white balls. Shade Balls , Albedo Balls (sic)

    Xex LeaderXex Leader17 hours ago
  • Uhhh huhuhuh huhuhhehehheeehee ...you said 'balls.'

    TsujanryoTsujanryo17 hours ago
  • *So many people in the comments who skip the video and ask stupid questions*

    GoldenYuriGoldenYuri17 hours ago
  • Ok but is the propeller chopping up the balls

    theFareulookinattheFareulookinat17 hours ago
  • Black actually attracts heat rather than deflect it, in common sense, they fucked up, badly.

    Matthew LalibertyMatthew Laliberty17 hours ago
  • That's a lot of balls.

    Marvel JamesMarvel James17 hours ago
  • I don't like those perfect formations, itchy

    187onaPigeon187onaPigeon18 hours ago
  • Great now I’ve spent 12 minutes of my life learning what does Black Balls do

    Prince AliPrince Ali18 hours ago
  • Their main purpose is to reduce evaporation.

    MrGenedancingmachineMrGenedancingmachine18 hours ago
  • Cali diverter auqua duct water dot to go to imperial valley farms ranches frit grove trees sent the mountaint snow melt water into the pacific ocen then farmers rancers cant pay land property tax. Up for sale cheep just like oklahoma dust bowl farmers lost land wealthy families baught for way low of what the back taxes. Oklahoma similar to texas oil/natual gas rich land changed hands at a steel

    John HumphrysJohn Humphrys18 hours ago
  • Ooh my god this video is very annoying I finally watched it.

    just Qjust Q18 hours ago
  • A large milktea......

    facebookfacebook18 hours ago
  • Crap ... in full definition!

    Robert EllisRobert Ellis18 hours ago
  • Okay US-vision I watched it

    dragonball slayer326dragonball slayer32618 hours ago
  • What a absolute mad lad legend

    dragonball slayer326dragonball slayer32618 hours ago
  • Can you run across the reservoir now?

    sealand000sealand00019 hours ago
  • So they destroyed a natural habitat for the seagulls?

    Kenneth JaegerKenneth Jaeger19 hours ago
  • 5:50 woosh!

    ChrisTzouveChrisTzouve19 hours ago
  • Doesn't the surface area increase from wetting? In fact it will be close to 4 times now. But I guess the input heat transferred per unit area from solar radiation is still the area of the lake. It is just that the black balls would absorb more heat as it is pointed out in the video. However, if the material of the ball is a bad conductor, then most of the heat is radiated back, I guess. Am I thinking about this correctly?

    Manc CheeseManc Cheese19 hours ago
  • Don’t those balls still release BPA’s into the drinking water?

    Andrea SommerAndrea Sommer19 hours ago
  • So they spent $36,000,000.00 on these balls?

    James ChadwellJames Chadwell19 hours ago
  • plastic ain't good to consume... Black absorb Heat... SUN beating Down !! DRINK UP !! DUMBASSES

    D'Alene ParoleD'Alene Parole19 hours ago
  • Nobody: ... Conservative dad when he finds 48million black men hiding in his daughter's closet:

    dominicdominic19 hours ago
  • Anyone else see that bird fly into that plane engine? 5:50

    Starline272Starline27219 hours ago
  • And this is why we have 12 years to live

    Reggie StanleyReggie Stanley19 hours ago
  • They must have crappy,salty,fertilizer laden water to have a problem with sunlight and fresh air causing "harm". What they are doing is making a dirt bottom storage tank. As those black balls age..and they will,what's the lifespan before they DO start to break down and release all those chemicals into drinking water? They should have just put in water hyacinth..down there its pretty much evergreen.

    Stan TheObserverStan TheObserver20 hours ago
  • It's summer I didn't want to learn But now I'm happy that I did

    Beary BearingtonBeary Bearington20 hours ago
  • All those black balls; the Kardashian sisters must be salivating right now....

    Kevin RobertsKevin Roberts20 hours ago
  • Look I don't care what any of these RV people tell you if you don't have a bathroom and you're disgusting! LOL. You don't need a kitchen you need a bathroom. You should always start a campfire cook outside go to Wawa microwave something but you must have a bathroom or you are immediately put into the gross category. have a nice day

    Robert HarrisRobert Harris20 hours ago
  • Plastic in water/food = end of lifeform on earth

    AngelrebirthAngelrebirth20 hours ago
  • GTA should add these in an update.

    OddgeirOddgeir20 hours ago
  • 0:01 When it’s the last day of school

    SirGeckoSirGecko20 hours ago
  • Black balls absorb heat. White would have reflected heat.

    marioamayaflamencomarioamayaflamenco20 hours ago
  • Thank you Mr. Stark, very cool.

    ミニシュミニシュ20 hours ago
  • They spent $32,000,000 on these plastic balls, damn..

    Lenny WilsonLenny Wilson20 hours ago
  • 5:52 is it just me or did that bird just get decapitated??

    Tyler MyersTyler Myers20 hours ago
  • This seems completely insane, I work for the Water Industry in the UK. Just looked it up, in the USA they do have open-air treated water reservoirs. In the UK once the water has been treated it then goes to service reservoirs basically covered holding tanks. Once the water leaves the treatment plant it's an entirely enclosed system, great steps are taken to ensure the water isn't contaminated, by anything. Maybe I'm missing something, but how on earth can an open-air treated water reservoir be a good idea. The risk of contamination is insane, people, animals, general debris and the boat. The excerpt below is from an article where 38m gallons of water had to be dumped because of someone peeing in a Portland reservoir. "The urine poses little risk - animals routinely deposit waste without creating a public health crisis" seriously what, this flies in the face of everything I've ever learnt about water quality.

    Persistent GamerPersistent Gamer20 hours ago
  • There goes the reservoir!

    wrnjpn qazwrnjpn qaz20 hours ago
  • With all the plastic pollution this will be what the oceans will look like in 50 years

    TomJoeSHOWTomJoeSHOW21 hour ago
  • I bet you wish all those black balls were in your ass. BooYaa!

    omgwtfbbqomgwtfbbq21 hour ago
  • Cool

    SuperSaiyan ZeroSuperSaiyan Zero21 hour ago
  • "Why are 96,000,000 black balls on this reservoir?" Because American police cut them off 48,000,000 black men.

    Keith BallardKeith Ballard21 hour ago
  • 32,000,000 for balls

    YouCan'tFlimFlam TheZimZamYouCan'tFlimFlam TheZimZam21 hour ago
  • Shade balls are small plastic spheres floated on top of a reservoir for environmental reasons, including to slow evaporation and prevent sunlight from causing reactions among chemical compounds present in the water. Also known as bird balls, they were developed initially to prevent birds from landing on bodies of water. Save yourself 13 minutes of your life.

    Benjamin HamiltonBenjamin Hamilton21 hour ago
  • They are sick. Leave the nature alone then it will be much better.

    Krupinski YoutubeKrupinski Youtube21 hour ago
  • At 5:53 you could see a big bird being sucked by the engine while plane is running the tarmac.

    Arthur OcampoArthur Ocampo21 hour ago
  • bro.... mate...

    Charlotte AveryCharlotte Avery21 hour ago
  • Might attract something else...time will tell

    weerobotweerobot22 hours ago
  • Did they add a sound effect for the bird getting turned into minced meat at 5:50?

    Vishal BandaruVishal Bandaru22 hours ago
  • The factory who sold plastic balls for 30c per piece is laughing their balls off.

    FyarFyar22 hours ago
  • So.. if you live there and leave your glass of clean drinking water in the sun a bit too long it will have become carcinogenic.

    FyarFyar22 hours ago
Why Are 96,000,000 Black Balls on This Reservoir?