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.




  • It’s rare to see 96 million of anything Beach sand : Hold my beer

    Tony XanxTony XanxPřed 2 hodinami
  • the proble is that you cannot swim, and you die faster

    Mocanu Catalin CristiMocanu Catalin CristiPřed 2 hodinami
  • did someone calculate how much does that reservoire cost ? 96 million balls and how much money ?

    Mocanu Catalin CristiMocanu Catalin CristiPřed 2 hodinami
  • TL;DW: The balls block out the sunlight from triggering a reaction in the water where bromide (harmless) would react with chlorine to form bromate (carcinogen.)

    Jeremy LandigJeremy LandigPřed 2 hodinami
  • hmmm that is a lot of rubber plastic, how will you collect them from the reservoir ?

    Mocanu Catalin CristiMocanu Catalin CristiPřed 2 hodinami
  • So y'all drive boats in drinking water?

    Joshua ScottJoshua ScottPřed 2 hodinami
  • This is what happens when Walmart buys a Chuck-E-Cheese franchise

    Jonathan PerryJonathan PerryPřed 3 hodinami
  • Now I am confused why all reservoirs do not have these. all cities have the water supply so why does this not happen elsewhere ?

    R.T. WeedermannR.T. WeedermannPřed 4 hodinami
  • they can use white balls. White surface bounces light from the sun rather than the black colored balls w/c absorb light.

    Patata0kePatata0kePřed 5 hodinami
  • Where in LA? Can we go see it publicly? I might have a chance to see it since I live in Cali lol

    {feather_cloud}{feather_cloud}Před 5 hodinami
  • RIP that one bird that got sucked in

    {feather_cloud}{feather_cloud}Před 5 hodinami
  • Be a bit hard to fish ?

    dudekiwidudekiwiPřed 5 hodinami
  • WTH! Just because it’s food grade plastic, does not mean it’s safe to eat! What a dingdong! Just made me question the whole project. Also, I’m wondering why the filtering and cleaning doesn’t happen AFTER the reservoir.

    Lynne VoyleLynne VoylePřed 6 hodinami
  • So how long were people consuming carcinogenic water before they realised the water was carconegenic, and made these balls?

    benselby87benselby87Před 7 hodinami
  • It soo satisying when they were on the boat and the boat moved it

    alex twinalex twinPřed 7 hodinami
  • *Imagine An Ef5 Tornado Spreading These All Over The Place* 😂

    BonkersGamesBonkersGamesPřed 8 hodinami
  • Wow Minecraft has come to life!

    EchoEv1EchoEv1Před 9 hodinami
  • The bromide ion is antiepileptic, andbromide salts are still used as such, particularly in veterinary medicine.Bromide ion is excreted by the kidneys. ... Chronic toxicity from bromide can result in bromism, a syndrome with multiple neurological symptoms.Bromide toxicity can also cause a type of skin eruption.

    Morwen BezuidenhoutMorwen BezuidenhoutPřed 11 hodinami
  • Camouflaging the fact that water is underneath... The question is why...

    Morwen BezuidenhoutMorwen BezuidenhoutPřed 11 hodinami
  • Sounds suspect. Those Balls can be filled with any type of poison. Its called Population Control

    Wanda FoxxWanda FoxxPřed 11 hodinami
  • is swimming possible ?

    HenryHenryPřed 11 hodinami
  • It’s the best solution at this time.

    Lim Kok HwaLim Kok HwaPřed 12 hodinami
  • the was a cheaper way, just take the plastic from the atlantic and put that in your lake :P

    Gaming With StefanGaming With StefanPřed 12 hodinami
  • why not white doesn't it reflect light better?

    ronald millierronald millierPřed 13 hodinami
  • Plastic is toxic. Donald Trump delivers a speech on the environment from the White House - watch live ch-visions.com/detail/video-fDQuO1nm_NY.html

    François ValléeFrançois ValléePřed 13 hodinami
  • Who wants to see him eat one ..since he is so sure they are safe 🙄

    Amanda DevierAmanda DevierPřed 13 hodinami
  • Ok youtube, you win

    Josue DavidJosue DavidPřed 13 hodinami
  • This video was a load of balls. What's boba(?)

    bletheringfoolbletheringfoolPřed 13 hodinami
  • when the shade balls parted with the water I immediately thought of Moses

    Joe InfernoJoe InfernoPřed 13 hodinami
  • 6:43: Difficult to prevent a reaction that violates conservation of mass! Seriously, though, I guess this is why L.A. tap water is no longer chlorinated to the point of undrinkability, which is certainly a pretty big additional benefit.

    DanHarkless ﴾Halloween videos, YTPs, & more﴿DanHarkless ﴾Halloween videos, YTPs, & more﴿Před 15 hodinami

    Barbara Stepien-foadBarbara Stepien-foadPřed 15 hodinami
  • What an amazing video. It is not just shade balls, the narration and filming are so very good.

    Sunil GSunil GPřed 15 hodinami
  • Clickbait

    FinanzFerdinand BetaFinanzFerdinand BetaPřed 16 hodinami
  • The dead sea

    Simom BreedsSimom BreedsPřed 16 hodinami
  • All the birds have gone.all the fish all the insects and thats OK 🤔 nope

    Simom BreedsSimom BreedsPřed 16 hodinami
    • very small area to bring drinking water to the desert ,LA to supply water to Millions of people Prevents who knows how many Hundred thousand gallons of Chlorine being pumped in . Yes the good outweighs the bad Bird poop in drinking water Bad. Your point is taken .This is not natural

      Greg GoodGreg GoodPřed 12 hodinami
  • Mmm plastic to drink.

    Du FungDu FungPřed 17 hodinami
  • Water in L.A., keep throwing chemicals until you get cancer by drinking water. Fantastic job! Clap clap clap clap clap

    Gabi PinaGabi PinaPřed 17 hodinami
  • This is great. (: In today's world every single problem will have a solution with the help of using more plastics, oil and other forms of energy. And they will all create more problems to be solved by great scientists. Evil circle more looks like it.

    Miklós DávidMiklós DávidPřed 18 hodinami
  • Great, more plastic, just what we need. No doubt some minute particles of plastic from those balls will be leaking in to the water.

    Jesus and Mary, Inseparable - Flat Earth CatholicJesus and Mary, Inseparable - Flat Earth CatholicPřed 18 hodinami
  • That's racist..

    I Love SushiI Love SushiPřed 18 hodinami
  • Black balls omg how much african man must be killed for this black balls

    Ivan VujovićIvan VujovićPřed 21 hodinou
  • youtube forced me this video down my throat for about 3 months straight

    MotivmotionMotivmotionPřed 21 hodinou
  • We have trout and salmon and other fish in our reservoirs and they feed on Mayfly and other flying insects. If we used that system in our country it would surely kill them all off. There is no way we would use these balls in our reservoirs.

    STHFGDBYSTHFGDBYPřed 22 hodinami
  • What about the marine life in there ? Imagine , living ur life without sun !!

    Waqas MaqboolWaqas MaqboolPřed 22 hodinami
  • The plastic is probably not safe in the water, there will be some degredation and consumption of it.

    bixxybearbixxybearPřed 22 hodinami
  • Rest In Peace, seagull. 5:51 got killed by a airplane. Yeah. That’s only the point I care about in this video. Lmfao.

    Bradey BurtonBradey BurtonPřed 23 hodinami
  • 😑

    Sherry PatrickSherry PatrickPřed 23 hodinami
  • "The black additive [in the balls] is carbon black, which isn’t supposed to be harmful when it leaches, which is great. Yet even with this precaution, most plastics leach endocrine disrupting chemicals that interfere with animal and human hormone systems (Yang 2011). Some endocrine disruptors, like bisphenol A (BPA), break down in water after a few weeks or months. Some don’t. We don’t know what chemicals are in the Shade Balls, but they will leach, especially because the balls are in the hot sun and are meant to be left in the water over a long period (reports say 10 years). Most water treatment systems don’t take these kinds of chemicals out of the water." --- FAIL! grist.org/article/why-shade-balls-arent-such-a-great-idea-after-all/

    Bobby ClementeBobby ClementePřed 23 hodinami
  • Watch at 5:52 when the Thai Airways plane's jet engine sucks in a bird (RIP) right after the guy speaks of using these balls at ponds near airports to prevent....waterfowl from getting sucked into jet engines. Dang, son!

    Bobby ClementeBobby ClementePřed dnem
  • What are the balls made of? Are they made with BPA?

    Lemon DropLemon DropPřed dnem
  • they talked abt the birds like they were criminals

    LocNinjaXLocNinjaXPřed dnem
  • hoax

    Lexi BeckerLexi BeckerPřed dnem
  • The concept of "shade balls" really does work in the hot, sunny countries where it has been implemented...because they obviously are not the idiots that comprise California government and actually understand scientific principles. By which I mean, every other locale which has utilized this concept has correctly used WHITE balls. Because, SCIENCE. #dumbasses TL;DR: "The only color that does not attract heat is white because white objects reflect all visible wavelengths of light. Black⁠-the color that absorbs all visible wavelengths of light⁠-attracts the most heat." sciencing.com/colors-attract-heat-8715744.html

    Crystal BoyceCrystal BoycePřed dnem
  • Black Balls Matter! Drink up.

    TruthSeekerTruthSeekerPřed dnem
  • Looks like boba, she's got a pretty mouth 🤪 say boba again

    NYTFHS Oh YeahNYTFHS Oh YeahPřed dnem
  • It's ok to drive a motor boat in the drinking water 🤔🤔🤔

    NYTFHS Oh YeahNYTFHS Oh YeahPřed dnem
  • *_that's a lot of black balls_*

    Colour BarzColour BarzPřed dnem
  • RIP Bird in jet engine. At least it was quick and painless.

    ShadowsFrostShadowsFrostPřed dnem
    • Oh snap, you saw it too!

      Bobby ClementeBobby ClementePřed dnem
  • 6:45 7:07 7:11

    Cause EffectCause EffectPřed dnem
  • This should be good in the desert.

    uzzyvickuzzyvickPřed dnem
  • Wait... What? You're telling me that between the filtration plant and the customers is only an open air reservoir? There has to be more to it than that. What if an animal died in there? What if some psycho decided to poison the entire thing? I must be missing something.

    Taylor ParrishTaylor ParrishPřed dnem
  • something wrong with black balls?

    Nathan SmoreNathan SmorePřed dnem
  • Now I want to take one and bite it😂

    Toshi WoshiToshi WoshiPřed dnem
  • Why not white to keep the surface cooler??

    Mona MeMona MePřed dnem
  • That's still 32 million dollars worth of balls, plus delivery!

    SweetpeaSweetpeaPřed dnem
  • I would just have to wonder if they needed the Chlorine Actually. Why not Hydrogen Peroxide? H2O2? And skip the "shade ball" wildness? Maybe they should still be in the chem/plant lab? What about plants? The plastic balls are weird, not to mention expensive.

    SweetpeaSweetpeaPřed dnem
  • Anyone else is allergic or has trypanophobia who got bothered by just seeing the clustered black balls? It feels uncomfortable. May we heal one day and be back here to enjoy this!!!!

    Taghreed SobhiTaghreed SobhiPřed dnem
  • Is this in Sylmar California??

    Oscar GutierrezOscar GutierrezPřed dnem
  • They should never ride a boat in the reservoir!!!! People drink the water dahhh

    Andrew MartinAndrew MartinPřed dnem
  • the question i had in mind was: Will blocking the sunlight cause microbes to multiply in the water ?!

    [SGL] Gaming[SGL] GamingPřed dnem
Why Are 96,000,000 Black Balls on This Reservoir?