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.




  • What's with the mobbed up looking guy on the boat with the slicked back hair? Making sure noone talks?

  • 96 million plastic balls all bumping and grinding and having boats driven through them, no possibility of micro plastic problems?

    rorybone100rorybone1003 часа назад
  • So the reservoir is between the filtration plant and the customers? But why? I would have expect the other way. So people are drinking water directly from a lake full of decomposing plastic? That must be very healthy...

    Marius BancilaMarius Bancila3 часа назад
  • In Africa there's no clean water to drink.

    ಕೃಷ್ಣಾ ಭಾಗವತಕೃಷ್ಣಾ ಭಾಗವತ4 часа назад
  • 5:49 the bird got sucked! 💔💔

    Chesco ZamChesco Zam5 часов назад
  • I now have PTSD knowing this bird died in vain for this video.

    Arch YeomansArch Yeomans5 часов назад
  • Why don't they use an Air boat aka Fan boat ?

    checkdraycheckdray6 часов назад
  • I'm pretty sure all those black balls showed up because there's a lot of hot white women nearby. That's how it works

    Brownie McCocoaBrownie McCocoa6 часов назад
  • 20K angry gay boys disliked this video

    Officer Meow Meow FuzzyfaceOfficer Meow Meow Fuzzyface8 часов назад
    • angry misappropriated reassignment candidates...anyone got 2020 in their sights?

      Jessica WalkerJessica Walker7 часов назад
  • Worthless RUvision AI algorithm spam

    Dee DeeDee Dee8 часов назад
  • Cool video

    Ann ReyesAnn Reyes8 часов назад
  • Bromide, chloride, fluoride are ALL bad forms halide; all bad halogens. Iodide is the only beneficial one. Ok, some scientist is going to say this all technically wrong but.....Any fluoride, fluordine, bromide, bromine, bromain, chloride, chlorine are bad. Iodine is the only halogen that is good for human beings. Yes, a couple compounds may be wrong or nonexistant and my grammar incorrect, however, I believe many will get the gist of what I am saying.

    DAVID Mc__________DAVID Mc__________8 часов назад
  • Why wouldn't they just filter the water as it leaves the reservoir? This probably fucked up the ecosystem for any wildlife that lived there.

    KhankhistoKhankhisto9 часов назад

    buck ewerbuck ewer10 часов назад
  • What would happen if someone fell off the boat? Can you swim in that?

    Cyrus BurkeCyrus Burke10 часов назад
  • if someone falls in, it will be dangerous.

    鼓嘶鸣鼓嘶鸣10 часов назад
  • So....why isnt every other city having this bromate problem?

    Aaron FramptonAaron Frampton10 часов назад
  • This is so unnatural solution, blocking sun ? sun makes water live.. water is life .. live.. hope the scientist could think natural.. so many problems already because of just focusing on solution to 1 problem .. its horrible way indeed..

    milinda Vashishthmilinda Vashishth10 часов назад
  • this is why wee gonna die to ouer self what are the do whit all those balls when ther finish in the balls well lets dump them in nature becors good for the nature and wee are smart human ......

    Smithdk1234Smithdk123410 часов назад
  • Could you not use a hovercraft instead of a boat? Balls are said fine in wind. But mainly I agree with Joanne Marks below, any plastic in water releases Estrogen like chemicals. I don't like to be racist like a certain president but this is a typical American high tech approach to fix a problem. Is there not a lower tech solution? that does not involve putting plastic micro-particles and estrogen chemicals into peoples water. How about the impact on wildlife? How about the solution used by the ottomans, underground cisterns. see en.wikipedia.org/wiki/Basilica_Cistern

    Derek DayDerek Day11 часов назад
  • Because 95 million would be ridiculous??

    Deez TittsDeez Titts11 часов назад
  • and how do I get the job of driving around in a boat ?

    TahoedirtTahoedirt12 часов назад
  • 🌹🌷💐 لا إله إلا الله ، محمد رسول الله 💐🌷🌹 There is no GOD but ALLAH, MUHAMMED is the Messenger of ALLAH🌹🌷💐 لا إله إلا الله ، محمد رسول الله 💐🌷🌹 There is no GOD but ALLAH, MUHAMMED is the Messenger of ALLAH🌹🌷💐 لا إله إلا الله ، محمد رسول الله 💐🌷🌹 There is no GOD but ALLAH, MUHAMMED is the Messenger of ALLAH🌹🌷💐 لا إله إلا الله ، محمد رسول الله 💐🌷🌹 There is no GOD but ALLAH, MUHAMMED is the Messenger of ALLAH🌹🌷💐 لا إله إلا الله ، محمد رسول الله 💐🌷🌹 There is no GOD but ALLAH, MUHAMMED is the Messenger of ALLAH

    شفير القيامةشفير القيامة12 часов назад
  • 1:27 This guy really looks and sounds like Christian Bale as Dick Cheney in Vice!

    Tanja Isabel AebischerTanja Isabel Aebischer12 часов назад
  • I thought based on the title that this was about the million man march.

    Jouc12 _Jouc12 _12 часов назад
  • so some suckerass of a berkley student can make the world a better place by whoring himselfs out to a buncha degenerated asshats on YT to fall for his crapass clickbait. the fukc is wrong with the tube lately. it was always a fkn dirthole but lately we went from dirty to filthy.

    Smoke YaSsSmoke YaSs13 часов назад
  • Why not 100,000,000? ...104,000,000? Maxed out the credit card?

    Jeff WallerJeff Waller14 часов назад
  • Seems like white balls would reflect heat and cool the surface better than black.

    Jeff WallerJeff Waller14 часов назад
  • that bs. seems like thoose inbred la hollywood jewish scum dont even know the effect of sunlought @ water !!! SUCH A FRAUD & HOAX !!! LMFAO

    Doxpara anameDoxpara aname14 часов назад
  • Why the world so against black anything if it's proven black is best not racist antics just science

    KingThugga TvKingThugga Tv14 часов назад
  • NPR talking going on here, many pauses....don't know if I can watch ....the whole thing. My question....why? IS this how he talks to his mom? His dad? His significant other? Who knows and who cares?

    Kristopher ChristensenKristopher Christensen14 часов назад
  • 5:53 RIP BIRD.

    AAA HHHAAA HHH15 часов назад
    • 5:51

      AAA HHHAAA HHH15 часов назад
  • Everything causes cancer in California..........

    Niterunner77Niterunner7715 часов назад
  • thats alotta black balls

    Zack GrayZack Gray15 часов назад
  • 5:52 - BRUTAL!!!

    HMJHMJ15 часов назад
  • 1:49 - Imagine these black balls having mouths and jagged teeth on their own and chasing the nutritious human explorer in a jet boat. XD

    HMJHMJ15 часов назад
  • These are GANTZ balls.

    HMJHMJ15 часов назад
  • 48,000,000 black men were NOT harmed in the making of these balls. =)

    Vodka TonicVodka Tonic16 часов назад
  • I think that's where McDonald's got the idea for their play places!

    Vodka TonicVodka Tonic16 часов назад
  • she clearly wanted you to ask her out on a boba date lol

    Vikram UpVikram Up17 часов назад
  • Think that's a 10th of Donald Trump's quids.

    michael wardsmichael wards18 часов назад
  • Nice meme

    Jessie MedinaJessie Medina18 часов назад
  • Hmm, wireless solar absorbing balls?

    Mehrunes VlahdiaMehrunes Vlahdia18 часов назад
  • Rasist hey why are they black

    Elite RiezzElite Riezz18 часов назад
  • Putting gasoline from a boat motor in a water reservoir, not smart.

    Robert WilliamRobert William19 часов назад
  • Algae ?

    brian bondbrian bond20 часов назад
  • the best think is you can walk on water :D

    Dark -ShadowDark -Shadow20 часов назад
  • Sounds like a Kardashian joke

    Brandon SimonBrandon Simon21 час назад
  • Thy should shot a horror movie in this place!

    Lucas Soares CoutinhoLucas Soares Coutinho22 часа назад
  • The seagull at 5:50!

    Through the bulkheadThrough the bulkhead22 часа назад
  • UMMM anyone else see the bird get minced by the plane propeller at 5:50 ? lol

    PixelliaPixellia23 часа назад
  • 5:50 R.I.P bird

    Mayhem ManiacMayhem ManiacДень назад
  • i was wtachnig this video then on min 5:52.... a bird got sucked into the jet engine!

    Chaim ChaitChaim ChaitДень назад
  • What about the birds?

    7 -137 -13День назад
  • hmmmm looks to me like they are hiding something in the water.............

    cascaradepollo cascaradepollocascaradepollo cascaradepolloДень назад
  • 3 to the dollar.96*3=32 mil.Nice one.

    Stephen GrangeStephen GrangeДень назад
  • one day there gonna mess up on something and have humans drink poison

    ScorponkillerScorponkillerДень назад
  • 20 years from now.. ...sorry la.. those balls actually cause cancer... our bad!

    IwonIwonДень назад
  • Its like a bad science project gone kinda wrong....

    Jesse AllenJesse AllenДень назад
  • One word: baaaaaaaalls.

    D. S.D. S.День назад
  • This is how u throw ur plastic garbage legaly.

    jack remoladojack remoladoДень назад
  • it is not proper system i think

    SK Daily EntertainmentSK Daily EntertainmentДень назад
  • My biggest question is why are they in that boat driving around on drinking water?

    ShaunieBNaturalistaShaunieBNaturalistaДень назад
    • Considering how many billions of gallons there are in that reservoir any possible leaked contaminants from the boat would impact the water in parts per billion which is far lower than the parts per million regulations on most substances. At least that’s my tale on it I don’t work for LA water.

      unamericanounamericano4 часа назад
  • That bird got fucked up

    Jay A.Jay A.День назад
  • Only the Kardashian girls has seen more black balls.

    T1971 C1971T1971 C1971День назад
  • Oh, I was gonna guess there was 48 million black guys swimming in that lake. The Bro-Mate kinda confirmed it

    koiesbowkoiesbowДень назад
  • Please like and subscribe to my channel. Thanks ruvision.net/pass/UCwFE636PTRGJ79sI8WaLkSg

    Byahe KoByahe KoДень назад
  • Because 48 million black men have been castrated

    jadekayak01jadekayak01День назад
  • How would they make out in a waterspout? How much hotter is it above the balls? is it like being on a black roof? What causes a water spout?

    Bob LoblawBob LoblawДень назад
  • So if treated water sitting in the sun creates carcinogens, what about every other drinking water reservoir that doesn't have black balls blocking the sun?

    Andrew LambertAndrew LambertДень назад
Why Are 96,000,000 Black Balls on This Reservoir?