It’s easy to take water for granted. After all, you just turn a faucet and it pours right out. But how does it get to our faucet? We’ll explore the water cycle from rain to your drain. And did you know that space is full of water? It’s one of the most common features of the universe. We’ll also look at all the important things our bodies do with water — and how that’s a cycle too. Caution: this episode may make you very thirsty.

Or download the episode here or from iTunes!

Marc with George and Ian
Producer Marc Sanchez with water quality manager George Kraynick and co-host Ian.
Molly Bloom
Water pump at Minneapolis Water Treatment Plant
Water pump at Minneapolis Water Treatment Plant
Molly Bloom
Low service pumps
Low service pumps
Molly Bloom
Pipes underneath the Minneapolis water treatment facility
Pipes underneath the Minneapolis water treatment facility
Molly Bloom

George and Ian after the tour
George and Ian after the tour
Molly Bloom

Audio Transcript

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ANNOUNCER: You're listening to Brains On!, where we get curious about the science of everything.

MOLLY BLOOM: These sounds--




--they're all around us. And while they may be so commonplace that we barely think about them, they're really important to what we do every day.

IAN MCKIM: Yeah, they are a pretty big deal, so how come I don't know where the water comes from? How does it get to my house?

MOLLY BLOOM: Let's find out right now.


CHILDREN: Brains On!

MOLLY BLOOM: You're listening to Brains On! from Minnesota Public Radio News and Southern California Public Radio. I'm Molly Bloom, and here to help us get to the bottom of where our water comes from is 11-year-old Ian McKim. Hi, Ian.


MOLLY BLOOM: Before we actually get to how water gets to your shower or sink, let's take a big step back and think about where the water comes from before it reaches our homes.

IAN MCKIM: First of all, water is a cool substance.

MOLLY BLOOM: We could spend an entire episode talking about the cool properties of water. But what we're most concerned with at the moment is how water is the only natural substance on Earth that exists in all three different states.

IAN MCKIM: It exists as a solid.

MOLLY BLOOM: Like ice.



IAN MCKIM: And a liquid.

MOLLY BLOOM: Like, well, water. Liquid water. [SIPS] [SWALLOWS] Aah!

IAN MCKIM: Water, moving through its different forms, is constantly going through a cycle. In fact, in nature, the same water moves around and around from clouds to rain to lakes and rivers back to clouds. It's called the water cycle. Here, check it out.


WOMAN: The water in oceans, lakes, and rivers is evaporated by the sun. Plants also sweat their water into the air through a process called transpiration. These water vapors float into the sky.

When they get cold, they condense and form clouds. The clouds make rain and snow sending water back to the Earth filling the oceans, lakes, and rivers, and nourishing plants. The water in oceans, lakes, and rivers is evaporated--

MOLLY BLOOM: I think we get the idea.

IAN MCKIM: Right, the water cycle goes on and on and on and on. It seems to be never-ending. In fact, the same water you are drinking today was once drunk by cavemen.

MOLLY BLOOM: Dinosaurs bathed in it. It was even there when the first life-forms on the planet developed billions of years ago.

IAN MCKIM: The same water has been with us for a very long time. It just gets recycled a lot. But it had to get here somehow.


SURFER 1: Killer waves today, dude. This water is gnarly.

SURFER 2: Yeah, totes, brah.

SURFER 1: Hey, have you ever like wondered where water comes from?

SURFER 2: It comes from rain, dude.

SURFER 1: Yeah, but where does rain come from?

SURFER 2: Well, it's simple. I mean, everybody knows like rain is-- whoa, I don't know.

NARRATOR: I know where the water comes from.



SURFER 1: Who are you?

NARRATOR: I'm the narrator of this skit. And water comes from (ECHOES) space, space, space, space.


SURFER 1: Space water? What do you mean?

NARRATOR: Have you ever heard of something called the Big Bang?

SURFER 1: Oh, isn't that Chris's band? You know, like the one with four drummers, dude.

SURFER 2: [CHUCKLES] Yeah, they shred.


SURFERS: We are the Big Bang causing thunder wherever we hang.

SURFER 1: Yeah!

NARRATOR: No, no! Not Chris's band. The scientific theory of the Big Bang. It's the origin of the universe as we know it.

SURFER 1: Please, elaborate.


NARRATOR: 14 billion years ago, the entire universe was crammed into a very tiny dot. Everything was smooshed in there. Then it suddenly exploded out creating space and time itself. That's the Big Bang part. When this explosion happened. It scattered lots of material, most of which was hydrogen.


SURFER 1: Uh, yes, the lightest of all the elements, dude. It's represented by the letter H on the periodic table and consists of one proton with one electron circling it.

NARRATOR: Wait, ser-- wait, seriously? You knew all that?

SURFER 1: Shah, you think all I do is surf? I'm getting a degree in biochemical engineering, bro. Got to pay the bills.

NARRATOR: Um, Oh, OK, wow. Um, oh, whatever. Yeah, well, yes, hydrogen was spread across the universe after the Big Bang. But, of course, water is a combination of elements, that's why we call it H2O. Hydrogen is the H and the O is-- oxygen.

SURFER 2: Oven mitts.

NARRATOR: Wait. Wait, did you say oven mitts?

SURFER 2: Yeah. Am I right?

SURFER 1: Excuse my friend, narrator dude. He fell off his skateboard as a kid, a lot.

NARRATOR: Oh, right. Uh, let me just get to the point. You need hydrogen and oxygen to form water, but where did the oxygen come from?

SURFER 2: I don't know!

NARRATOR: After all, just after the Big Bang, the universe was made almost completely of hydrogen and helium, no oxygen at all. Well, some of that hydrogen and helium combined to form stars.

SURFER 2: Like our sun!

NARRATOR: There you go. You're getting it. Now stars burn up hydrogen at super hot temperatures like a giant oven.

This process creates lots of other elements, including oxygen. But the really, really big stars burn quickly. And they run out of fuel and when that happens, they explode in what's called a supernova.

SURFER 2: Kaboom!

NARRATOR: Yes, uh, kaboom. The explosion scatters all the newly created elements from the star back out into the universe. So hydrogen, oxygen, and everything else made in the star is free to mix around and combine into different molecules. It's some serious space chemistry.

SURFER 2: Like you and Kelly, bruh. [CHUCKLES] You guys have some serious chemistry. [CHUCKLES]

SURFER 1: What? No! We're just lab partners, dude. It's totally professional.

NARRATOR: Focus, guys, I am almost done here.


NARRATOR: Uh, where was I? Oh, yeah, as it turns out, the most common molecule that forms from all this interstellar chemistry is H2O or water. Our universe is filled with it. It's on our planets, in comets, and floating in clouds in interstellar space. Water is, in fact, everywhere.

SURFER 2: Surf's up in space.

NARRATOR: So when our Earth was formed around 4 and 1/2 billion years ago, it was made out of all sorts of floating space stuff, including water. And over time, the planet was hit by a lot of comets. These also carried water, adding even more H2O to our planet's surface. So that, my friends, is where water comes from.

SURFER 2: Whoa, water's from space. Sick science, man, for real. I like totally learned something. But wait, how are the oven mitts involved again?

NARRATOR: Is he always like this?

SURFER 1: Some days, it's worse. It's best to just go with it, dude.

SURFER 2: OK, wait. The big bagel created stars. And they were so hot you need oven mitts. No, that's still not right.

SURFER 1: Hey, bro, let's hit the waves again. Surf's up.

SURFER 2: Oh, what? Oh, yeah, let's surf!


MOLLY BLOOM: So as you're pondering the mysteries of the universe, I have another mystery for you. It's time for the mystery sound.


GIRL: Mystery sound.

MOLLY BLOOM: Here it is.


Think you know what it is? You can find out if you're right a little later in the show.

SINGERS: (SINGING) Ba, ba, ba, ba, ba, ba, ba, ba, ba, ba, ba, Brains On!


IAN MCKIM: And I'm Ian.

MOLLY BLOOM: And today on Brains On! we're dipping our toes into water. Well, not really. There's a lot of equipment here that we don't want to get wet, so maybe I should let Ian ask the question.

IAN MCKIM: How does water get to my house?

MOLLY BLOOM: To find out, Ian and I visited the water treatment plant that provides water to the whole city of Minneapolis and also a number of suburbs.

IAN MCKIM: Water quality manager George Kraynick was our guide.

GEORGE KRAYNICK: We take our water from the Mississippi River. That is our sole source. So the building we're in right now is the softening plant. So we take a lot of the minerals out of the water because the water is really loaded with minerals. We do that part in this building.

And then we send the water over to our filter plant, where we disinfect the water and actually physically filter the water. And then from there, we add a little bit of fluoride for dental purposes. And then it goes out into the distribution system.

IAN MCKIM: Why aren't there fish coming out of my faucet at home?

GEORGE KRAYNICK: [CHUCKLES] Well, we have multiple barriers to keep the fish out. So we pull the water from the river, but we actually have screens that keep the river debris out, which would include fish. We don't want fish in our process. And plus, when we disinfect the water, fish don't like chlorine. If anybody has a fish tank, then they know right off the bat you have to take the chlorine out of the water or else it'll kill the fish, so that's another step in the process.

IAN MCKIM: So you said you filter the water?


IAN MCKIM: I know there's a lot of tiny organisms that could get through a filter. How are those taken out? Is the filter so small that even those can't get through?

GEORGE KRAYNICK: Yeah. The Columbia Heights plant is a perfect example. It uses membrane technology, so it's a ultrafiltration membrane plant. So if you would pluck out a human hair, the diameter of that human hair is 100 microns.

The filter pore size of Columbia Heights is 0.03 microns. So imagine how small that is. So that effectively removes any type of bacteria. There are some viruses that are tiny and tricky and can sneak through, but that's why we chlorinate the water as well.

MOLLY BLOOM: George brought us to one of the pump stations where they bring in water from the Mississippi and filter it and then pump it out to get processed further.

GEORGE KRAYNICK: So back behind me, we have what are called bar screens on the outside. So they're basically just a screen to keep all the big stuff from coming in. We see everything in the river, mannequin heads, basketballs. You name it, people throw it in the river. We want to keep that stuff out of our intakes and out of our pumps, so that's our first barrier.

We have at least two of everything. We have five intake chambers. You saw all those pumps in there. We are always pumping water 24 hours a day, seven days a week.

So if something falls apart or needs repair, we take it out of service. And life goes on, we keep pumping the water. But you'll see that over and over again, multiple redundancies.


We've got lots of crazy things here. A lot of people don't realize that under every street, there's a water main. And under every house, there's a water line coming into your house that brings the water into you.

So what we're going to do now is we're going to go into the pump station. And I'm not going to talk too much in there because it's kind of loud.


IAN MCKIM: So why is thing making so much noise?

GEORGE KRAYNICK: Why is it making so much noise?


GEORGE KRAYNICK: That's just the hum of the motors. That sound.

IAN MCKIM: How does the water get to my house?

GEORGE KRAYNICK: So it gets to your house by really those blue pumps at pump station five, that's it. They pump the water out. It goes into the big 48-inch water main that circles the city. And then it goes through smaller pipes, smaller pipes, smaller pipes, until it comes to your house.


GEORGE KRAYNICK: Yeah. So if you go down into your basement, you'll see probably a copper pipe coming through the wall or coming through the floor. There'll be a water meter there. The pumps are making the pressure, the pumps are always running, sustaining that pressure throughout the system, so it's always there. So when you open the tap the water comes out.


MOLLY BLOOM: So now when you drink water, what are you going to think about?

IAN MCKIM: I'm going to think about how-- the big process they go through just to get me this glass of water. It's definitely a lot bigger process than most people would think, even I thought.

MOLLY BLOOM: Yeah, I was surprised, too. It was-- a lot happens to our water before it gets to our house.

IAN MCKIM: Yeah, there's a lot of-- there's a pump station, the softening, a lot of different things it goes through before it can be distributed to Minneapolis.

MOLLY BLOOM: Let's go back to that mystery sound.


What a beautiful sound. I could listen to that all day. Do you have any guesses?

IAN MCKIM: Is it the sound that came from all those motors in pump station five?

MOLLY BLOOM: That is very, very close. Have you ever been staring out the window in a car and thought, hey, what's that big lollipop-looking thing shooting up out of the ground? Think of a broomstick with a basketball balanced on top.

Now enlarge your picture about a hundred times, paint the name of a city in big letters on the ball, and it will look like where today's mystery sound came from. It's a water tower. The sound is actually of the pumps moving clean treated water up to the water towers in Richfield, Minnesota.

So it's not the plant that we were at, but it's a similar kind of situation there. Minneapolis doesn't use water towers, but many cities across the country do. To find out why, we spoke to Richfield City Engineer Kristin Asher.

KRISTIN ASHER: Although you may remember a time when you had to go without electricity for a short while, you'd be hard-pressed to recall a time when you turned the handle on the sink and water did not come out. And the big reason you can count on that is the water tower. So a water tower is a large, tall tank of water.

And they can hold up to one day's worth of water in case of emergencies. That's usually somewhere around 1 million gallons or more. A large swimming pool is about 20,000 gallons, so it'd be about 50 large swimming pools.

And the water is supplied to the houses through pressure. And the reason that towers are up so high is because the height builds pressure. And so if there was a power outage and you had no power in your house, your water should still run because we've got water in the tanks. And that pressure can be built up whether or not the pumps are powered.

MOLLY BLOOM: If you've seen a cool water tower near where you live send us a photo. You can visit our website


IAN MCKIM: Water seems to have a thing for cycles. Speaking of which, let's check in on our water cycle and see how it's doing.

WOMAN: The water in oceans, lakes, and rivers is evaporated by the sun. Plants also sweat their water into the air through a process called transpiration.

MOLLY BLOOM: Yep, still going. Water moves through a cycle on Earth, but It also moves through a cycle in the city.

IAN MCKIM: In Minneapolis, water comes from the river, goes to the water treatment plant, and then gets pumped into our houses.

MOLLY BLOOM: After we use the water, it goes down the drain, goes to a sewage treatment plant where they clean the water, and then it goes back to the river.

IAN MCKIM: Water also goes through a cycle in our bodies.

MOLLY BLOOM: Our bodies are somewhere between 55% and 78% water depending on how old you are.

IAN MCKIM: The older you get, the less water is in your body.

MOLLY BLOOM: So you actually probably have more water than me. I better drink some more to catch up. [SIPS] [SWALLOWS] Aah!

FACTORIUM SPEAKER 1: Welcome to the factorium.

FACTORIUM SPEAKER 2: Dr. Lisa Anderson of the University of Minnesota has stored three facts here regarding water in the body.


LISA ANDERSON: We take the food that we eat and we turn it into a form of chemical energy that the cells can understand. And in that process, we're breathing in oxygen. And then we take that oxygen, and, as part of the process, we convert it into water. So water is actually a product of the stuff that's going on in our cells.


LISA ANDERSON: In order to get rid of our waste, we have to produce a certain amount of urine. And we have to drink a certain amount of water just to replace that. And as we're exhaling, as we're sweating, we're also losing water.


LISA ANDERSON: If you were to add up all the water or all the volume of fluid in your body, actually, most of it is inside your cells. Water in your blood, which is called plasma, that's maybe three liters. And so for people, imagine a two-liter bottle of soda, you have three liters of that fluid in your bloodstream.

Maybe there's more like 28 liters of fluid actually inside your cells. And you think, well, a little tiny cell is microscopic. That's true, but there are billions of them. And when you add that all up, it ends up being a huge volume of fluid.

FACTORIUM SPEAKER 2: Thank you for visiting the factorium. Please, come again soon.


JOE DEGOERGE: I'm a water molecule floating in a reservoir. I've been in the sky, and I've been in a dinosaur. I'll swim through copper pipes and bubble through your walls and floor. I'll meet you at the sink, and dance on your lips when you take a drink.

Yeah, I'm a water molecule, sloshing round your mouth. I'm going through your body, and there's water all around. Most of it is in your cells.

In the cytosol between membranes. Water is the medium for growth and communication of your body cellular information. Without the water in your cell's cytoplasm, there'd be no way to grow, to be loving and laughing. Yeah.

I'm the water in your eyes. I'm the water in your spine. I'm the water in your mucous.

You need water all the time. I'm the water in your guts. I'm the water in your cells.

I'm the water in your hair. Water is more than half your cells. I'm the water in your bones.

I'm the water in your blood. I'm the water in your brains. Yeah, this body is a flood. I'm the water. Water.

I'm a water molecule. And I'll get the jobs done that your body needs to function just surround me with ions. And I know there is a time when you'll need to send me off.

To discharge your waste or with some sputum in your cough. Oh, I could leave in the body vapor when you shout. And I'll make you seem cold if you happen to sweat me out. Yeah, I'm a water molecule.

And I [INAUDIBLE] in your body through your poop or your spit or vomit or your pee. Then I'll be free, off to the sky through the sea. With a small probability, I'll be back in your body.


IAN MCKIM: That was Joe DeGeorge. You might know him from his band Harry in the Potters.

MOLLY BLOOM: And that was the song, "I'm a Water Molecule."

IAN MCKIM: Water cycles through our lives in lots of ways.

WOMAN: The water in oceans, lakes, and rivers is evaporated by the sun. Plants also sweat their water into the air.

MOLLY AND IAN: We get it!

IAN MCKIM: The same water keeps cycling through the air back to Earth.

MOLLY BLOOM: It cycles through pipes from rivers, lakes, or aquifers to and from our homes.

IAN MCKIM: And it cycles through our bodies.

MOLLY BLOOM: But this episode can't keep cycling through forever. It's just about over. You can always visit our website, to listen to past episodes. And you can subscribe at iTunes or one of your favorite podcast apps.

IAN MCKIM: This episode was produced by Marc Sanchez, Sanden Totten, and Molly Bloom.


IAN MCKIM: Also thanks to Nathan Crockett from Caltech and Emily Lakdawalla and Bruce Betts of the Planetary Society for helping with the space science on today's show. Thanks for listening.


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