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

  • Published on:  5/10/2019
  • 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 http://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.


  • Tiznado (May 10, 2019)

    Veritasium: It’s really rare to see 96 million of anythingSand grains: Am I joke to you?

  • O Orange (9 minutes ago)

    It's rare to see 96 million of views

  • KurtCobain (25 minutes ago)

    U.S. Debt Clock: Am I a joke to you?

  • knight rider (20 hours ago)

    Its very rare to see 96 million of anything.9yo army: pff

  • fly5 (1 hour ago)

    +Hxrman j only 9 year olds or all ages who he calls 9 year olds?

  • Nolia (2 hours ago)

    I’m here for the meme

  • Johnson B Vadakkethala  (11 hours ago)

    any body here after his " how my video took off " video 🤣🤣🤣

  • Ted Johnson (24 minutes ago)

    Yes! I avoided this video until now because of the clickbaity title.

  • Johnson B Vadakkethala (3 hours ago)

    +Thomas Cusack thanks bro

  • Hit Reset Button (1 day ago)

    This guy explaining bromate is fantastic...why can't we have more public servants and politicians like him...he is serious, concerned and engaging all in one...fantastic!!!!

  • Jason Greenman (54 minutes ago)

    William Mulholland was like that too

  • JessieJ (3 hours ago)

    Meanwhile that politician is getting richer from the income tax you pay every week with every one of your pay checks while you get more poor every year as he keeps raising your income tax percentage

  • jManraM (22 hours ago)

    5:51 RIP birdie that got sucked in to the turbine

  • AnthonydoesYouTube (1 hour ago)

    Lol dumb bird chose the wrong moment to take off, what a BIRD BRAIN

  • lincbond442 (2 hours ago)

    You can see the remains shoot out the exhaust.

  • Gamer Awesome45630 (May 12, 2019)

    They used these balls to trap Mr. Incredible.

  • This is something Morgz would do...After seeing a MrBeast video

  • Giving away 96 million black balls🤪😮😮💯👏👏

  • Alice Ribeiro (6 hours ago)

    Or a killem vid

  • THE ULTIMATE (10 hours ago)

    Anyone here after watching how to get a video viral

  • Shwetank Chandra (1 hour ago)

    Me lol😁😁

  • lannoene (3 hours ago)


  • TK Tang (7 hours ago)

    I'm so glad Veritasium's video went viral. It's brilliant

  • squirrel punk (1 day ago)

    Bird:* flying around minding it's own business *Airplane engine : *YOUR FREE TRIAL OF BEING ALIVE HAS ENDED*

  • Johnny Mneumonic (1 hour ago)

    squirrel punk “Life is like a free trial it’s pretty good but it ends too soon” - squirrel spunk

  • Oliver Jepp (1 hour ago)

    +Domino52o hahahh life free trial.. that's funny